BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) ZOOLOGY VOL. VI 1959-1960 PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM (NATURAL HISTORY) LONDON: 1960 DATES OF PUBLICATION OF THE PARTS No. i. 23 October 1959 No. 2. 19 February 1960 No. 3. n March 1960 No. 4. ii March 1960 No. 5. ii March 1960 No. 6. 12 April 1960 No. 7. 22 July 1960 PRINTED IN GREAT BRITAIN AT THE BARTHOLOMEW PRESS DORKING BY ADLARD AND SON, LTD. CONTENTS ZOOLOGY VOLUME 6 PAGE No. i. Taxonomy of the genus Columba. By D. GOODWIN i No. 2. A revision of the Platyseiinae (Mesostigmata: Aceosejidae) based on material in the collections of the British Museum (Natural History) . By G. OWEN EVANS and K. H. HYATT 25 No. 3. British slugs (Pulmonata: Testacellidae, Arionidae, Limacidae). By H. E. QUICK (Pis. 1-2) 103 No. 4. A revision of the Lake Victoria Haplochromis species (Pisces, Cichlidae) Part IV. By P. H. GREENWOOD 227 No. 5. On a Stygiomysis from the West Indies, with a note on Spelaeogriphus (Crustacea, Peracarida). By ISABELLA GORDON (Pis. 3-4) 283 No. 6. Contributions toward a classification of modern Isospondylous fishes. By WILLIAM A. GOSLINE 325 No. 7. The ecology and taxonomy of some Angola birds (Based on a collection made in 1957). By B. P. HALL (Pis. 5-6) 367 Index to Volume 6 455 TAXONOMY OF THE GENUS COLUMBA D. GOODWIN BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) ZOOLOGY Vol. 6 No. i LONDON: 1959 TAXONOMY OF THE GENUS COLUMBA BY D. GOODWIN Pp. 1-23 ; 5 Text-figures BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) ZOOLOGY Vol. 6 No. i LONDON : 1959 THE BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY), instituted in 1949, is issued in five series corresponding to the Departments of the Museum, and an Historical Series. Parts will appear at irregular intervals as they become ready. Volumes will contain about three or four hundred pages, and will not necessarily be completed within one calendar year. This paper is Vol. 6, No. i of the Zoological series. Trustees of the British Museum, 1959 PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM Issued October, 1959 Price Nine Shillings TAXONOMY OF THE GENUS COLUMBA By D. GOODWIN CONTENTS Page INTRODUCTION ........... i COLOUR AND COLOUR-PATTERN . . . . . . . i ADAPTIVE RADIATION AND RELATIONSHIPS ...... 2 THE SPECIES-GROUPS AND THEIR COMPONENT SPECIES .... 4 NOTES ON SPECIES .......... 7 SUMMARY ............ 22 REFERENCES ........... 22 SYNOPSIS Previous reviews of the genus Columba have grouped together species which lack display plumage on the neck or whose ornamentation is superficially similar. This is believed to have resulted in some false conclusions because such display plumage has been independently lost or become obsolescent in several species. When this is recognized and greater importance attached to basic colour-patterns and geographical distribution a truer picture of relationships within the genus can be arrived at. INTRODUCTION THE genus Columba includes a large number of medium to large-sized pigeons, widely distributed throughout the world. Peters (1937), for example, lists fifty-two species and does not divide them into sub-genera. The rather inconveniently large size of the genus has often been criticized and the affinities of its members questioned. Ridgway (1916) separated the relatively few northern and central American species into six genera, some of them monotypic. The most important recent revision of the genus is that of Boetticher (1954), who divides it into several sub-genera and corrects some false conclusions of a previous and less comprehensive revision by Miculicz- Radecki (1949). When re-arranging the very extensive collection of specimens of Columba in the British Museum (Natural History) it was found impossible to agree with all of Boetticher's conclusions. The object of this paper, therefore, is a revision of the genus based on examination of the skins in the National Collection and correlated, as far as has been possible, with what is known of the ecology and behaviour of the species of which it is comprised. Emphasis is placed on discussion of those points where my conclusions differ from those of Boetticher. I am indebted to Dr. Dean Amadon of the American Museum of Natural History for the loan of specimens of Columba albinucha and C. pallidiceps, to Mr. J. D. Macdonald for help and con- structive criticism and to Dr. G. Bodenstein, Professor W. F. Hollander and Mr. R. W. Sims for information and discussion on various points. COLOUR AND COLOUR-PATTERN Within Columba plumage colour ranges from entirely black, with green and purple iridescence, to predominantly pale grey or purplish-chestnut. It is evident that, ZOOL. 6, I. I TAXONOMY OF THE GENUS COLUMBA as in Ptilinopus (Cain, 1954) colour-pattern is usually a better guide to relationship than actual colour. One finds striking differences in the colour of the plumage and/ or soft parts of the head and neck (the focal area of both sexual attraction and aggres- sive attack in pigeons) between pairs of sympatric and very closely related species as C. squamosa and C. leucocephala or C. rupestris and C. leuconota (see Text-fig, i). KEY TO SHADING Dull purple or purplish-brown Iridescent green &XX3 Iridescent purple or wine-red Black or greyish-black, glossed with green in fallidiccfs White or silver-grey y. i { { i\ Display plumage with dark feather- ) ) ) ) ) edges giving a scale-like appearance FIG. i. Diagrammatic sketches to show differences in head and neck colours between three pairs of sympatric and closely related species. From top left : pallidiceps and vitiensis, squamosa and leucocephala, rupestris and leuconota. Such differences almost certainly function as isolating mechanisms to inhibit inter- specific pairing. Signal markings on wings and tail and specific differences in voice and display-flight serve the same purpose at " longer range ". As with other groups of birds the greatest diversity of signal markings, display plumage and voice is found where there are many related and at least potentially sympatric species and, conversely, a tendency to lose such characters and acquire a dull uniformly coloured plumage in isolated island forms. Lack of signal markings or display plumage in Columba seems never to be a primitive character. Examination of the colour- pattern and other characters of the species concerned shows convincingly that their common lack of ornamentation is due to convergence and not to close affinity. Sexual dimorphism in Columba is relatively slight but in most species it is sufficient to enable skins or living birds to be correctly sexed on plumage colour alone. In those species which are predominantly grey males are a purer, bluer grey than females. Purple, chestnut or mauve-pink in males is often duller, absent, or replaced by dull brown in females. Iridescent display plumage (when present) is usually more brilliant in males. Where adults show such differences of plumage similar and homo- logous sexual differences are found in the juvenile plumage. ADAPTIVE RADIATION AND RELATIONSHIPS Adaptive radiation can be misleading at generic level, since once two forms have evolved marked differences of size and structure they are unlikely to be considered TAXONOMY OF THE GENUS COLUMBA 3 con-generic. For example the many Australian bronze-wing pigeons are obviously very close relatives in spite of the taxonomically convenient differences in size and proportions which they have developed in the course of adaptation to different ecological niches. Within Columba, as here recognized, the greatest amount of adaptive radiation is found among the Palearctic and Ethiopian species. Similar, but less marked differences are shown among the American species, but here maculosa, which otherwise closely parallels the old-world lima, has not emancipated itself from the use of trees for resting and breeding. The question arises whether the New World representatives of Columba should be generically separated from the Old World forms. Cumley & Irwin (1944) concluded from their work on the antigenic inter-relationships of the blood cells of guinea, livia, palumbus, janthina, fasciata, maculosa, picazuro, cayennensis, flavirostris and leucocephala that each of the six American species was more closely related to the other five than to any of the four Eurasian species. Verheyen (1957) considers that skeletal differences warrant the separation of Old and New World forms of Columba, both of which groups he further divides into several genera, some of them monotypic. I am not competent to criticize Verheyen's opinions in so far as they are based on osteology, but his decisions placing guinea in the monotypic genus Dialiptila and generically separating janthina, vitiensis and norfolciensis are so contrary to the evidence from external taxonomic characters and behaviour-patterns that I hesitate to follow his conclusions without further evidence. If the New World species are to be generically separated this could be done only on osteological and biochemical characters. Possibly studies currently in progress in America will show that there are constant and significant behavioural differences also and it will be desirable to separate the American from the Old World species. I think, however, that at present it would be premature to do so. It seems to me best to retain the large genus Columba as used by Peters (1937) and Hellmayr & Conover (1942) but to give Oenoenas and Turturoena sub-generic rank within it. I also think that Nesoenas should be given only sub-generic rank within Columba. The remaining forms can be relegated to five species-groups. Cain (1954), in his revision of the pigeons in the genus Ptiliuopus, used the category of the species-group for " an informal natural group of closely related species below the rank of a subgenus, the recognition of which involves no complication of the scientific names of the species contained in it." And that of sub-group for more closely related forms within the species-group. I have followed Cain in the use of these categories which are equally useful for defining relationships of the pigeons hi Columba. The hierarchy of categories is therefore : Genus Sub-genus Species-group Sub-groups (of species group) Superspecies Species Subspecies ZOOL. 6, I. r 4 TAXONOMY OF THE GENUS COLUMBA There are, naturally, some species whose characters show them to be inter- mediate between two sub-groups and it has been necessary to allot them somewhat arbitrarily to that with which they seem to have most in common or else to place them in a mono-specific sub-group. All such cases are discussed below. In the following list members of the same superspecies are bracketed together. Sub- species have not been listed but they are discussed under the species headings where they are relevant to specific problems. THE SPECIES-GROUPS AND THEIR COMPONENT SPECIES (i) Oenas Species-group Smallish (oliviae) to large (trocaz) sized columbids inhabiting the Palearctic and Ethiopian regions, one species (livia) also occurring in India, and throughout much of the world in a feral state as a result of human introduction. Most species in this group have well developed display plumage on the neck and patterned tails. Sexual dimorphism slight. (a) Palumbus Sub-group Tail rather long with conspicuous pale central band ; breast mauve-pink or salmon-pink. C. palumbus Linnaeus, 1758 C. trocaz Heineken, 1829 C. bollii Godman, 1872 C. unicincta Cassin, 1859 (1860) (b) Oenas Sub-group Glossless mauve-pink on head and/or breast, black signal markings on inner wing-coverts (obsolescent in oliviae). C. oenas Linnaeus, 1758 C. eversmanni Bonaparte, 1856 C. oliviae Stephenson Clarke, 1918 (c) Livia Sub-group No glossless mauve-pink colour on breast or head. Display plumage on front as well as sides of neck (absent in leuconota). C. livia Gmelin, 1789 C. rupestris Pallas, 1811 C. leuconota Vigors, 1831 C. guinea Linnaeus, 1758 C. albitorques Riippell 1837 TAXONOMY OF THE GENUS COLUMBA 5 (2) Junioniae Species-group Large columbid inhabiting the western Canary Islands of Palma and Gomera. Mantle and wings dark brown and immaculate ; tail with broad pale terminal band. Entire neck and breast iridescent but no well differentiated display plumage. One species C. junioniae Hartert, 1916. (3) Elphinstonii Species-group Smallish medium to large-sized columbids inhabiting the Indo-malayan and Ethi- opian regions. All except one with unpatterned tails. No signal markings on wings. Most with display plumage on sides and back of neck. (a) Arquatrix Sub-group Display plumage on hind neck lanceolate. Wing-coverts and /or underparts spotted with white (obsolescent spots in polleni}. {C. arquatrix Temmink, 1809 C. pollenii Schlegel, 1866 C. hodgsonii Vigors, 1832 C. albinucha Sassi, 1911 (b) Elphinstonii Sub-group Display plumage on hind neck of black feathers tipped white or buff. Iridescent green or purple sheen on neck and mantle. Unpatterned tails, no signal markings on wings. One superspecies. {C. pulchricollis Blyth, 1845 (1846) C. elphinstonii (Sykes, 1832) C. torringtoni Bonaparte, 1854 (c) Punicea Sub-group No well differentiated display plumage on neck ; wing coverts and body plumage immaculate chestnut or silver contrasting with black primaries. C. punicea Blyth, 1842 C. argentina Bonaparte, 1855 (d) Palumboides Sub-group Head and neck silver-grey ; wings and back dark grey with iridescent feather edges. One species. C. palumboides (Hume, 1873) (4) Janthina Species-group Large columbids inhabiting the Pacific regions from Japan to Australia, chiefly on islands. Plumage largely or entirely blackish and highly iridescent. No signal markings on wings ; dark unpatterned tails. Not divisible into sub-groups. 6 TAXONOMY OF THE GENUS COLUMBA {C. janthina Temminck, 1830 C. vitiensis Quoy & Gaimard, 1830 C. norfolciensis Latham, 1801 C. versicolor Kittlitz C. jouyi Stejneger, 1887 C. pallidiceps (Ramsay, 1877) (5) Picazuro Species-group Small (rufina) to medium-large (maculosa) columbids inhabiting the nearctic and neotropic regions. Most with display plumage on back and sides of neck and patterned tails. (a) Leucocephala Sub-group Patch of velvet-like feathers on nape ; well-defined iridescent display plumage on back and sides of neck. Plumage largely dark slate-grey ; wings and tail unmarked. C. leucocephala Linnaeus, 1758 C. squamosa Bonnaterre, 1792 (b) Speciosa Sub-group Feathers of neck and breast white and golden with dark, iridescent edges ; back, rump and wing-coverts purplish-chestnut (male) or dark brown (female). Tail blackish and unmarked. One species only. C. speciosa Gmelin, 1789 (c) Picazuro Sub-group Outer wing-coverts edged white ; mantle and wing-coverts brown, tail with ill- defined terminal dark band. C. picazuro Temminck, 1813 C. corensis Jacquin, 1784 C. maculosa Temminck, 1813 (d) Fasciata Sub-group Parti-coloured tail with broad, pale terminal band. Iridescent green display plumage on hind-neck. One superspecies. {C. fasciata Say, 1823 C. araucana Lesson, 1827 C. caribaea Jacquin, 1784 (e) Rufina Sub-group Small size. Crown and nape iridescent ; ill-defined pale terminal band on tail; plumage mainly vinous-purple. C. rufina Temminck, 1810 TAXONOMY OF THE GENUS COLUMBA 7 (f) Flavirostris Sub-group No iridescence on head or neck ; plumage largely vinous-purple ; tail dark grey without markings. One superspecies. {C '. flavirostris Wagler, 1831 C. oenops Salvin, 1895 C. inornata Vigors, 1827 Sub-genus Oenoenas Small columbids of central and southern America with dark brown and greyish- purple or reddish-purple plumage ; small bills, strongly rounded tails, obsolescent display plumage on hind neck and no markings on wings or tail. Consists of only four species. It seems purposeless to sub-divide further this small and very homo- geneous assemblage into sub-groups, which could only be done, if at all, on the shorter tails of two of them, nigrirostris and goodsoni. C. subvinacea (Lawrence, 1868) C. plumbea Vieillot, 1818 C. nigrirostris Sclater, 1859 (1860) C. goodsoni Hartert, 1902 Sub-genus Turturoena Small columbids inhabiting the Ethiopian region. Bright metallic iridescence on hind-neck. Marked sexual dimorphism except in the island form malherbii. One superspecies. {C. delagorguei Delagorgue, 1847 C. iriditorques Cassin, 1856 C. malherbii Verreaux & Verreaux, 1851 Sub-genus Nesoenas Large-sized Mauritian columbid with rounded wings (first primary about equal in length to sixth) and rufous tail. One species. C. mayeri Prevost, 1843 NOTES ON SPECIES C. palumbus The Wood Pigeon is considered by Boetticher (1954) to be most closely related to torringtoni, elphinstonii , trocaz and junioniae and to be much nearer to fasciata and allied American species than to oenas or unicincta. He grouped these, and some other pigeons, close together because they all show a high degree of ornamentation on the neck feathers, similar relative lengths of wing and tail and arboreal habits. Certainly the conspicuous white or cream-coloured patches on its neck give palumbus a superficial resemblance to such species as fasciata which also have con- spicuous white areas in the display plumage of the neck. In its colour-pattern and TAXONOMY OF THE GENUS COLUMBA TAXONOMY OF THE GENUS COLUMBA g even in the individual colours, however, it agrees more closely with unicincta and oenas. The difference in coloration of the display plumage on the necks of oenas and palumbus, due to the white patches of the latter, can be interpreted as an iso- lating mechanism (see Sibley, 1957) as can the difference in their advertising calls. The bowing display of palumbus is identical with that of oenas and its pre-copulatory behaviour is very similar to that of oenas, guinea and lima (see Goodwin, 19560) and differs from that oi fasciata as described by Whitman (1919). It is true that in some points of structure and deportment palumbus bears more resemblance to fasciata than to oenas but this may be attributed to the fact that palumbus and fasciata are largely arboreal and obtain much of their food from the tips of slender branches whereas oenas is almost entirely a ground feeder. Geographical distribution also seems to favour the linkage of palumbus and oenas. In my opinion, and excepting obvious derivatives on the Atlantic islands (see trocaz and bollii], palumbus has closest affinities with unicincta and is nearer to oenas than it is to pulchricollis or fasciata or to their close allies. At the same time its undoubted resemblance to these latter emphasize the difficulties of generically separating the Eurasian and American groups of Columba. C. trocaz The Madeiran Pigeon appears to be a fairly recent derivative of palumbus. In its voice and bowing display it closely resembles that species and in appearance it differs only in its slightly darker coloration, in lacking the white signal markings on the wings and in its slightly longer legs and more sloping forehead. As, however, it would seem to have diverged sufficiently not to have interbred with later Wood Pigeon invaders, now distinguished racially as C. palumbus maderensis, it has to be accorded specific rank. C. bollii Bolle's Pigeon is considered by Peters (1937) and others to be conspecific with trocaz. Both appear to be derivatives of palumbus but evidence suggests that they did not share a common ancestry subsequent to their differentiation from the parent stock. Although both have lost the white wing patch of palumbus the white neck patch has modified in different directions in each. In trocaz it has become a dull silvery grey and increased in area whereas in bollii it has become a small glossy brown mark. Since trocaz cannot now be considered conspecific with palumbus it seems better to give bollii specific status also. C. unicincta Boetticher considers the Afep Pigeon to be a relatively primitive species, most closely related to maculosa, because it lacks display plumage on the neck. It seems to me much more likely that loss of display plumage has occurred at a relatively late stage in the evolution of both species and does not indicate any close phylo- genetic relationship between them. In its general colour pattern unicincta agrees fairly closely with palumbus and its tail markings are identical with those of that io TAXONOMY OF THE GENUS COLUMBA species. Two features in which unicincta differs from palumbus are in its pale-edged wing-coverts and in its grey feet and bill. Since, however, these features, like the lack of iridescence on the neck, are similar to those in juveniles of palumbus I do not think they diminish the likelihood of close phylogenetic relationship of unicincta and palumbus, which their other features, including the little that has been recorded about the behaviour and ecology of unicincta, seem to indicate. C. oenas The Stock Dove is usually considered to be much more closely related to lima than to palumbus but in fact it forms a connecting link between the two in its taxo- nomic characters as well as in its ecology and behaviour (Goodwin, ig56a). Thus it agrees with palumbus in the distribution of the display plumage on its neck, in its glossless mauve-pink breast and in the form of its bowing display, but its wing and tail markings and its proportions are closer to lima. In view of the intermediate position of this, the type species of Columba, generic separation of " wood pigeons " and " rock pigeons " becomes untenable. C. eversmanni Eversmann's Stock Dove is extremely close to oenas in appearance, differing only in its smaller size, yellow irides and in having the head as well as the breast mauve- pink, or with a strong mauve-pink tinge, and in sometimes having a white instead of a grey rump. I concur with Peters in thinking that the evidence at present available warrants their both being considered full species. Stuart Baker (1928) put eversmanni as a race of oenas stating that " intermediate forms are not infrequent ". He gave no evidence for this other than mentioning some grey-rumped eversmanni having been obtained in Afghanistan. Except in this one feature grey-rumped individuals do not resemble oenas any more closely than do white-rumped ones. Stuart Baker's further remarks about the affinities of the two show that he knew little about the behaviour and ecology of oenas. The breeding range of eversmanni as indicated by Dementiev et al. (1951) has a considerable overlap with that of oenas. That they retain their respective characteristics where they are, apparently, sympatric, is evidence of their specific status. C. oliviae The Somaliland Pigeon can be regarded as forming a superspecies with eversmanni. The differences between them can be explained by the adaptation of oliviae to its torrid desert habitat. As well as acquiring a paler and browner coloration it has lost the black wing bars, probably quite recently, as many specimens show a few blackish flecks where these are in eversmanni. The loss of these signal markings may have resulted from a need for more perfect camouflage or simply to lack of selection for them subsequent to isolation from other closely related species. Unfortunately nothing appears to have been recorded of the behaviour or breeding habits of this species. In spite of its alternative vernacular name of " Somali Rock Pigeon ", oliviae is no more closely related to livia than are eversmanni or oenas. TAXONOMY OF THE GENUS COLUMBA n C. al orques The White-collared Pigeon has a white neck ring like that oifasciata and acuminate neck feathers like arquatrix. But as it resembles these species in no other respects it is highly unlikely that these likenesses indicate close relationship. Its tail pattern and the black markings on its wings seem to indicate relationship to oenas and lima. Taibell (1954) describes a bowing display like that of oenas. The lack of strong contrast between the black wing markings and their dark grey background, the slight degree of iridescence of the neck feathers and the partially concealed white wing patch may indicate that albitorques is at a stage of evolution where it is beginning to lose some of its display and signal markings, presumably as a result of being now ecologically isolated from related species. On the whole the appearance and taxonomic characters of this pigeon suggest a rather closer relationship with lima and guinea than with oenas and I have, accordingly, placed it in the lima sub-group. C. guinea It is fairly certain that the Speckled Pigeon is a close relative of lima (see Goodwin, 1956 and 19560) in spite of their differences of colour. They resemble each other in having display plumage on the front as well as on sides and back of the neck and in having the feathers of this display plumage bifurcated ; there are also many close resemblances of voice and behaviour. On the evidence of the blood antigens Cumley & Irwin showed that biochemically guinea is closer to palumbus than it is to lima or oenas. This is supported by two points of behaviour its calls and postures immediately after copulation and its methods of fighting. Thus what is known of this species emphasizes the essential homogeneity of the oenas species-group in spite of the rather considerable, if somewhat superficial, taxonomic and behavioural variations within it. I think, however, that in sub-dividing this group guinea should be put in the same sub-group as lima. C. leuconota The Snow Pigeon's plumage and general habits suggest a close relationship with lima and rupestris. The great differences in colour of the head and neck between leuconota and rupestris is almost certainly to be considered as an isolating mechanism and of little importance as an indicator of phylogenetic disparity. The same may be true of the apparently considerable difference between the voice and bowing display of leuconota (Newman, 1911) and that of lima. The black and white pattern on the tail of leuconota appears different from that of livia and other allied species but is essentially similar, the differences being due to a reduction of the black terminal band and an extension of the black basal area on the outer rectrices. C. livia The Rock Pigeon gives an impression of standing far apart from palumbus in appearance and behaviour. Boetticher (1954) indeed puts them as the terminal twigs on the two mutually diverging main branches of his family tree of Columba. The differences of form, behaviour and coloration shown by livia are largely due 12 TAXONOMY OF THE GENUS COLUMBA to its adaptations to nesting and sheltering in caves and rock fissures and feeding in open tree-less country. In fact I think that lima and palumbus are fundamentally much alike and that they represent the extremes in a single rather large species-group. Although lima now occurs in some moderately wooded regions it almost certainly evolved in a treeless or almost treeless environment. Its points of resemblance to rupestris, guinea and oenas are discussed under those species. C. rupestris The Blue Hill Pigeon is usually accorded specific rank although Austin (1948) put it as a race of livia but without giving reasons for this decision. Over most of their range the two are allopatric, rupestris replacing livia in the higher and colder parts of central and eastern Asia. The differences between them are certainly such as suggest racial rather than specific status. Rupestris has a proportionately smaller bill and a reduced amount of melanin in the plumage resulting in a white instead of a grey central bar in the tail, smaller black wing bars, paler grey ground colour and less intensely iridescent display plumage ; all differences such as might be expected in a race inhabiting a colder climate. With the possible exception of the white tail bar none of these cause as great difference in appearance as exists, for example, between C. livia gymnocyclus and C. /. dakhlae or C. L livia and C. I. intermedia. In its habits and ecology (Schafer, 1938) rupestris apparently differs in no essentials from livia. These facts suggest that the two are conspecific. On the other hand rupestris is said to associate with livia in parts of northern India (Stuart Baker, 1913) and it is potentially in contact with feral specimens of livia in many parts of its range. La Touche (1934) shot a specimen of C. livia intermedia (sic) out of a flock of rupestris in eastern China. The voice of rupestris, as described by Salim Ali (1949), would appear to differ much from that of livia. The evidence is thus conflicting. La Touche considers that the occurrence of mixed flocks suggest that rupestris and livia inter- breed but this might equally well be evidence to the contrary. If, as is likely, the term " mixed flock " has been applied to aggregations of rupestris and (? feral) livia at feeding grounds then such associations are of no significance either way. There are no specimens from among the many from North India and the Himalayas in the National Collection that appear to be hybrids or intergrades between the two. It must be admitted, however, that such birds might be difficult to detect, unless they were intermediate in coloration of the tail. Until the matter can be investigated more conclusively it seems best to accept the majority opinion that rupestris is a full species. Since the evidence suggests strongly that, at least as far as genuinely wild individuals are concerned, livia and rupestris are allopatric when breeding they should, I think, be considered members of a superspecies. C. junioniae The coloration and size of the Laurel Pigeon suggest relationship to palumbus. On the other hand the colour-pattern of its tail is similar to that of albinucha and fasciata. Meade- Waldo (1889) described it as having a very distinctive gait when TAXONOMY OF THE GENUS COLUMBA walking on the ground and a " soft, flopping flight " which was unlike that of any other pigeon known to him. He found that on the Island of Gomera, in the Canaries, it kept mainly to scrub-covered slopes at relatively low altitudes, being replaced in the high mountain forest by C. bollii. It lays one egg to a clutch. The Laurel Pigeon seems most likely to be either an offshoot from primitive palearctic Columba stock prior to its subsequent speciation or an early offshoot from palumbus. It is impossible to do more than guess at its affinities from an examination of skins and the little that has been recorded of its behaviour. A detailed comparison of its anatomical and behavioural characters with those of, at least, palumbus, fasciata and albinucha will probably be necessary before its true relationships can be ascer- tained. C. arquatrix Nominate arquatrix with a purple head, silver-grey nape and yellow bill and legs KEY TO SHADING Black or dark slate-grey Dark purple or dark purplish-chestnut Greyish-white or silver-grey Dark purple or purplish-chestnut with small white spots Dark purple with large pale grey spots Dark brown and purplish-brown Lanceolate display plumage with dark bases and shining tips to feathers FIG. 4. Diagrammatic sketches to show colours of the Arquatrix sub-group. Left to right : a. thomensis, a. sjostedti, a. arquatrix and (bottom) hodgsoni, polleni and albinucha. has always been considered, rightly in my opinion, conspecific with sjostedti from the Cameroon Mountains, which has an entirely dark grey head, red orange-tipped bill and dark purplish legs and feet. The Sao Thome representative, thomensis, is, however, currently given specific rank. It should, I think, be put as a race of arqua- trix. In plumage it is just a dull version of the latter with the spotting on wing- coverts and undersides and the lanceolate display plumage on the neck showing, apparently, the beginning of that obsolescence of markings that so often takes place in island forms. It otherwise shows characters of both mainland forms, having an 14 TAXONOMY OF THE GENUS COLUMBA entirely dark grey head like a. sjostedti but yellow legs and bill like a. arquatrix. It has a somewhat longer tail than either mainland form but this alone does not, in my opinion, warrant its specific separation from them. C. polleni* In spite of its almost uniform dark brown plumage polleni is also a representative of arquatrix. Although, presumably in the course of long isolation on the Comoro Islands, it has lost the rich colours of arquatrix it still retains lanceolate display plumage on the hind neck and the yellow legs and bill. Of three skins in the National Collection one shows faint pale spots on the underparts exactly similar to, though less pronounced than the spots of arquatrix. It has, however, reached a degree of differentiation from arquatrix that justifies, in my opinion, its specific rank, though it should be considered as forming a superspecies with arquatrix and hodgsoni. C. hodgsoni Verheyen (1955) considers this Indian species conspecific with arquatrix. That they are geographical representatives of the same stock cannot be doubted but hodgsoni differs from arquatrix in several minor points of coloration of plumage and soft parts and in its much greater sexual dimorphism. In view of this and of their wide geographic separation I think it is better to give them specific rank as members of the same superspecies. C. albinucha In coloration, colour-pattern and display plumage the White-naped Pigeon very closely resembles arquatrix. It differs in having red bill and feet, a patterned tail with conspicuous pale terminal bar and in lacking the white spots on the wing- coverts, although its underparts are spotted in the same manner as those of arquatrix. It is also a little smaller. The two are sympatric but their ecology and habitat preferences differ (Van Someren, 1949). Nothing seems to have been recorded of the displays, nesting or clutch-size of albinucha. Although there can be no doubt that they should be regarded as good species, the resemblances between albinucha and arquatrix are almost certainly due to close phylogenetic affinity and not to conver- gence. C. elphinstonii, C. pulchricollis and C. torringtoni Although differing in size and coloration these three forms all resemble each other in colour-pattern, form of display plumage and (so far as is recorded) in habits and ecology. It is difficult to decide whether it is best to treat them as races of a single * Through the kindness of Mr. C. W. Benson I have recently been able to examine the fine series of polleni collected on the B. O. U. Centenary Expedition to the Comoro Islands. These specimens show that the unsexed skins I had previously seen were all females and all somewhat "foxed". In fact males are a brownish purple on head, upper mantle and breast and the dark brown parts of both sexes are suffused with grey, especially on the rump. They thus resemble arquatrix more closely than I had thought and Mr. Benson informs me that the calls of the two are similar ; possibly identical. I. therefore, now consider that polleni should be treated as a race of arquatrix and not as a separate species. TAXONOMY OF THE GENUS COLUMBA 15 species or as members of a superspecies. Their ranges nowhere overlap and they have, presumably, been long isolated from contact with each other. As they have always been accorded specific rank it seems to me best to regard them as members of a superspecies. C. punicea The Purple Wood Pigeon most closely resembles argentina in colour-pattern although its purplish-chestnut body colour gives it a very different superficial appearance. This species is said sometimes to lay one and sometimes two eggs per clutch (Stuart Baker, 1913). If this is really the case no one other than Stuart Baker appears to have found nests with more than one egg this is an interesting intermediate condition between the species laying one egg and those laying two. C. argentina The Silver Pigeon shows a striking resemblance to the Pied Imperial Pigeons in colour and colour-pattern. Boetticher (1954) considered it more closely related to FIG. 5. Diagrammatic sketches to show colour-patterns of tails and outermost tail feathers of left, Ducula bicolor; right, Columba argentina. Ducula than to Columba. I have been unable to find any description of the anatomy of this pigeon which would show whether its stomach and intestines are of Ducula or Columba type. From its plumage characters, I think, however, that it is rightly placed in Columba. It shows the same type of sexual dimorphism female a slightly duller and browner grey in plumage colour as do other grey Columba species. It resembles punicea in the colour-pattern of its wings although the coloration of the two is different. Superficially the tail appears to be similarly marked to that of the Pied Imperial Pigeon but the pattern on the outer retrices (see Text-fig. 5) is quite different. I think, therefore, that argentina' s resemblance to the pied Ducula species is due to convergence and that it is best regarded as a rather aberrantly coloured member of the Elphinstonii species-group. It is another example of a Columba species which appears to have lost the display plumage on the neck, a point compatible with its presumed affinity to punicea which appears to show a regressional stage of this display plumage. C. palumboides In appearance, at least of the skin, the Andaman Wood Pigeon suggests a link between the Elphinstonii and Janthina species-groups. It seems likely to be nearer 16 TAXONOMY OF THE GENUS COLUMBA to the former on geographical grounds. Hume (1867) who collected some specimens and had a captive bird under observation was impressed by its " mode of holding itself and its broad substantial body " which he considered argued relationship to Ducula rather than to Columba. This may not be of importance as in so far as it is adapted to an arboreal life ; any large pigeon is bound to show some resemblance to Ducula as indeed does the common Wood Pigeon palumbus. A comparison of the alimentary tracts and a comprehensive study of the foods taken by this and other very arboreal Columba species with those of the Ducula species living in the same regions would be of great value. C. janthina The Black or Japanese Wood Pigeon and C. vitiensis, seem best considered as members of a single superspecies. C. j. nitens with its distinctive purple-brown head is somewhat intermediate, but in most respects is closer to nominate janthina than to any race of vitiensis. Stresemann (1939) suggests New Guinea as the place of origin of these forms and gives a map of their distribution and the probable directions of their former spread from the Papuan regions. C. vitiensis Although generally arboreal, so far as is known, C. v. halmaheira has been recorded nesting on the ground among thick cover (Warner, 1949) and Mr. I. C. J. Galbraith informs me that the natives on the Solomons told him that ground nesting was not infrequent in this species. In its bowing display (Newman, 1910) the bird moves rather slowly and does not erect its tail. C. norfolciensis This species appears to be a derivative of vitiensis. Males differ strikingly from the parent species in having the head and underparts white, or, in new plumage, creamy buff with a pink tinge. Females, however, have these parts whitish-grey or greyish-buff with some iridescence on the crown of the head and the pale throat as in vitiensis almost pure white and fairly clearly demarcated. Whether norfolciensis merits specific recognition is arguable but in view of the great difference in the appearance of the males, which makes it highly likely that if at some future period it were to invade the range of vitiensis or vice versa the two would not interbreed, and the nomenclatorial changes that would be involved, it seems preferable to accord it specific rank within the same superspecies. C. versicolor This extinct species appears to have been a very close relative of janthina. Kuroda (1925) considers it a race of janthina. Both forms occurred, however, on the Bonin Islands and I think therefore that Peters (1937) was right to give them specific rank in spite of their obvious affinities in form and coloration. TAXONOMY OF THE GENUS COLUMBA Q $ c'S O J3 I ll/ \ A o 2 ' I i 0> 4) 5 % g < 3 o I i 18 TAXONOMY OF THE GENUS COLUMBA C. jouyi Kuroda (1925) considers jouyi conspecific with janthina. Its distribution as given by him overlaps with nominate janthina on Okinawa. Jahn (1940) does not, however, record jouyi from Okinawa. Besides the large silver patch on its hind-neck and mantle which presumably functions as a recognition mark and probably also as an isolating mechanism -jouyi is a larger, longer-tailed bird and shows only slight traces of iridescence other than on the neck and nape. I therefore think it best to follow Peters in giving jouyi specific status. C. pallidiceps The Yellow-legged Pigeon appears to be a derivative from vitiensis stock. It now overlaps C. vitiensis halmaheira on some of the Solomon Islands (Mayr, 1934) although only pallidiceps occurs in New Britain, where it perhaps originated. Al- though much alike in general appearance the two differ strikingly in the coloration of the head, silver-grey in pallidiceps, dark purple with a white throat in vitiensis; and in the feet, which are red in vitiensis and yellow in pallidiceps. The coloration of pallidiceps is suggestive of that of norfolciensis (q.v.) whose close relationship to vitiensis is beyond doubt. It would be interesting to know if the difference in leg colour between the two serves in any way as an isolating mechanism. It would seem rather unlikely particularly as it is not correlated with any difference in bill colour, which is mainly red in both species. In other pairs of Columba species (e.g. arquatrix and albinucha) in which one has yellow and one red legs there is a correlated difference in bill colour. C. leucocephala The White-crowned Pigeon is very closely related to the Red-necked Pigeon C. squamosa. Both have the same highly-developed and beautifully (but differently) coloured display plumage on the back and sides of the neck, are of similar size and inhabit the same geographical areas. They may, however, be ecologically isolated as in Cuba (Barbour, 1943) ; leucocephala is a coastal and squamosa a highland form. The striking difference in coloration of the head, eyes and display plumage in these otherwise almost identical forms suggests that these differences function or have functioned as isolating mechanisms. It seems probable that this pigeon lays but one egg to a clutch (Wetmore and Swales, 1931) in spite of an earlier statement (Gundlach, 1874) that it lays two. C. squamosa The close relationship between the Red-necked and White-crowned pigeons has been discussed under leucocephala. The sexual dimorphism in squamosa is much less than in leucocephala but readily apparent when skins in a like state of plumage are compared. Probably this pigeon also lays only one egg (Wetmore, 1927) in spite of earlier statements (Gundlach, 1874) to the contrary. TAXONOMY OF THE GENUS COLUMBA 19 C. speciosa The Scaled Pigeon appears to be fairly close to sguamosa and leucocephala. In some respects its plumage is intermediate between that of these species and of picazuro but I do not agree with Verheyen that speciosa and picazuro should be generically separated from squamosa and leucocephala. In speciosa the dark edgings to the feathers are found throughout most of its plumage but are intensified in contrast and brilliance on the neck, thus giving a suggestion of the condition obtaining in leucocephala and squamosa. The Scaled Pigeon shows strong sexual dimorphism, the male having the mantle and wing-coverts rich purple (fading to chestnut) whereas those of the female are dull brown. C. picazuro The Picazuro Pigeon has the display plumage on the neck less highly developed than in leucocephala and squamosa but of an essentially similar kind. According to Hudson (1920) its habits, gait and behaviour are similar to those of palumbus but except for a vivid contrast of its gait on the ground with that of maculosa he gives no details. Hudson said that it lays two eggs, Venturi (see Hartert, 1909) that sometimes one and sometimes two eggs are laid. Wetmore (1926) found a nest with one egg. He also said that the display flight is like that of lima, a rather surprising fact in an essentially woodland species. C. corensis The Bare-eyed Pigeon can be considered as forming a superspecies together with picazuro. Its main differences, the much paler coloration and the very extensive amount of bare orbital skin, are probably adaptations to the hot, coastal areas where it lives. C. maculosa I think the Spotted Pigeon is most closely related to picazuro. It has evidently become more fully adapted to feeding on the ground in open country. Its resemblance in wing /tail proportions and gait to livia is almost certainly due to convergence in feeding habits. This is another species which has no display plumage on the neck, probably having lost it at a relatively recent date. If so, no close relationship to other species sharing this negative character is indicated. C. fasciata The Band-tailed Pigeon is reminiscent of C. arquatrix in its yellow bill and feet. The pattern of the bill is unusual in adult Columba but very much like that of Columba nestlings, only the dark sub-terminal band having " spread " to the tip of the bill and the lighter base turned bright yellow. The copulation ceremony of this species (Whitman, 1919) evidently differs in several details from that of European Columba species. 20 TAXONOMY OF THE GENUS COLUMBA C. araucana Although the Chilean Pigeon is very closely related to the southern form of the Band-tailed C . fasciata albilinea it has, I think, diverged sufficiently to be given specific rank. Besides the plumage differences (purplish-maroon on mantle and scapulars) it has a dark bill and red legs. It can be considered as forming a superspecies together with fasciata and caribaea. C. caribaea The Jamaican Band-tailed Pigeon is clearly derived either from fasciata, araucana or from some comparatively recent form ancestral to them both. In plumage it differs from fasciata only in being paler, in having lost the white neck-ring and having less well developed iridescent display plumage on the neck. It differs also in having, like araucana, a dark bill and red legs. C. cayennensis The Rufous Pigeon is intermediate in many respects between the members of the "fasciata " superspecies and those of the superspecies " flavirostris " . It resembles the former in the colour-pattern of its tail feathers and in having display plumage on the hind neck but in its other plumage characters it is closer to flavirostris . Little or nothing seems to be recorded about its breeding habits in the wild but two clutches of one egg each were laid by captive specimens (Newman, 1910). C. flavirostris The Red-billed Pigeon forms a superspecies together with oenops and inornata. All three completely lack display plumage on the neck thus presenting a superficial resemblance to the Oenoenas species. C. oenops This is the Peruvian representative of flavirostris. In appearance it differs only in the colour of its bill, which is yellow, or yellow tipped with black, instead of pink and whitish. Also the males have a larger area of ruddy purple on the plumage of the upper parts but females and juveniles are intermediate in this respect between males of their own species and flavirostris. C. inornata This island representative of flavirostris differs only in its larger size, black bill and grey, instead of red, orbital skin. The Sub-genus Oenoenas Salvadori (1893) characterized this sub-genus as having " general plumage, brown, more or less vinous, and with no light spots on the neck, but sometimes with concealed reddish spots, more or less obsolete, on the hind-neck ". Actually the " reddish spots " are appreciably lighter than the adjacent areas of the feathers TAXONOMY OF THE GENUS COLUMBA 21 that show them and these pigeons also have, as pointed out by Ridgway (1916), rather small bills and strongly rounded tails. Ridgway gave them, and others less deserving, full generic rank but subsequent authorities (Peters, 1937 ; Hellmayr & Conover, 1942 ; de Schaunsee, 1948) put Oenoenas into the synonymy of Columba. The four species concerned, plumbea, subvinacea, nigrirostris and goodsoni are all closely related and are more sharply differentiated than any others within Columba, mayeri excepted. I do not concur with Boetticher in considering them to be closely related to caribaea or that their dull concolorous plumage represents the retention of a primitive condition. The Oenoenas species differ from other Ameri- can pigeons (except for the quite differently coloured speciosa) in lacking grey on the rump, which is concolorous with the mantle and wings or nearly so. The more or less obsolescent pale or bronzy-red markings on the feathers of the hind-neck are more prominent in females than in males, which suggests that so far from repre- senting display plumage in process of acquisition, as Boetticher suggests, the reverse is the case. The obsolescent display plumage and general dull coloration of Oenoenas seems to be, in the evolutionary sense, a relatively recent development, not the retention of primitive characters. Oenoenas is most probably an early offshoot from the other American Columba that has diverged considerably from the parent stock. Its sombre, concolorous dress with complete lack of signal markings and obsolescent display plumage pre- sumably evolved as a consequence of increased predator pressure consequent on smaller size and /or increased reliance on vocal differences as isolating mechanisms. C. plumbea and C. subvinacea Only the fact that these pigeons appear to be sympatric in parts of their range, makes it possible on present knowledge to consider them as specifically distinct. Whilst the slight differences of colour and bill size make it possible to identify most specimens, it is difficult to believe that they could be sufficient to act as isolating mechanisms for the birds themselves. Presumably vocal and behavioural differences exist, but they do not appear to have been recorded. A few specimens in the National Collection are intermediate in character between plumbea and subvinacea but it is impossible to say whether these are hybrids or merely individuals whose slight aberrancy is towards the characters of the other species. C. nigrirostris and C. goodsoni These can certainly be regarded as forming a single superspecies. They may well be conspecific but since their taxonomic differences are at least as great (or one might better say no less) than those of plumbea and subvinacea, it seems better to grant them specific rank until more is known about them. The Sub-genus Turturoena This is comprised of three allopatric species delagorguei, iriditorques and malherbei which replace one another geographically and can be considered as forming a single superspecies. Salvadori (1893) separated Turturoena generically from Columba 22 TAXONOMY OF THE GENUS COLUMBA on its smaller size, hind neck with bright metallic colours and the sexes being often very dissimilar. Subsequent authorities have disagreed about its status, Peters (1937) placing it in the synonymy of Columba and Cave & Macdonald (1955) and Mackworth-Praed & Grant (1952) giving it full generic rank. I think, personally, that the differences do not merit more than sub-generic rank within Columba. Boetticher considers that Turturoena is more closely related to Aplopelia than to Columba. Certainly all three species have a similar distribution of iridescence to that of the Aplopelia species (but one found also in some species of Columba, and other pigeons) and a similar degree and type of sexual dimorphism. However, in my opinion, they show more affinities to the Columba species, not only in their general appearance but also in their colour-patterns which much resemble those found in palumbus and allied species. Mr. R. E. Moreau informs me (in litt.) that the cooing of delagorguei sharpei in Tanganyika reminded him very much of that of the Wood Pigeon, palumbus. The Sub-genus Nesoenas Salvador! (1893) placed the Mauritius Pigeon, C. mayeri, in the monotypic genus Nesoenas because of its more rounded wing, with the first primary about equal in length to the sixth, and its rufous tail. In coloration this pigeon does not closely resemble any other Columba but its colour-pattern shows some resemblance to the oenas species-group, from which it may possibly be an offshoot. Fortunately this species is not extinct as was at one time feared so it is possible that studies of it that will serve to indicate its affinities may yet be made. In the meantime I think it is better to put Nesoenas as a sub-genus within Columba than to afford it generic rank. SUMMARY This paper revises the genus Columba. The taxonomic and behavioural characters of the species are discussed in reference to their probable affinities. The absence or obsolescence of the display plumage on the neck is never a primitive character in Columba but one that has evolved independently in several species. Oenoenas, Turturoena and Nesoenas are given sub-generic rank. It does not seem feasible to further sub-divide the genus. There are indications that the American species may prove separable on anatomical and biochemical criteria although they cannot be separated on external characters. REFERENCES ALI, S. 1949. Indian Hill Birds. Oxford (p. 173). AUSTIN, O. L. 1948. The Birds of Korea. Bull. Mus. Comp. Zool. 101 (i) : 1-130. BAKER, E. C. STUART. 1913. Indian Pigeons and Doves. London. BARBOUR, E. 1943. Cuban Ornithology (Mem. Nuttall. Orn. Club. no. 9, pp. 70-72). BOETTICHER, H. VON. 1954. Die Taubengattung Columba L. Zool. Anzeiger, 153, 3-4 : 49-64. CAIN, A. J. 1954. Subdivisions of the genus Ptilinopus. Bull. Brit. Mus. (Nat. Hist.) Zool. 2, No. 8. TAXONOMY OF THE GENUS COLUMBA 23 CAVE, F. O. & MACDONALD, J. D. 1955. Birds of the Sudan. London. CUMLEY, R. W. & IRWIN, M. R. 1944- The correlation between antigenic composition and geographic range in the Old and New World of some species of Columba. Amer. Nat. LXVIII, No. 776 : 238-256. DEMENTIEV, G. P. et al. 1951. Birds of the Soviet Union, 11 : 6-32. GOODWIN, D. 1956. Remarks on the Rock and Speckled Pigeons. Bull. Brit. Orn. Club, 76 : 6-9. I956a. Observations on the voice and displays of certain pigeons. Avic. Mag. 62 : 17-33 and 62-70. GUNDLACH, J. 1874. Neue Beitrage zur Ornithologie Cubas. Journ. Orn. 1874 : 289. HARTERT, E. & VENTURI, S. 1909. Notes sur les oiseaux de la Republique Argentine. Novit. Zool. XVI, No. 2 : 260-261. HELLMAYR, C. E. & CONOVER, B. 1942. Catalogue of Birds of the Americas, pt. i, no. i, Zool. Ser. Field Mus. Nat. Hist. XIII, pt. i, No. i. HUDSON, W. H. 1920. Birds of La Plata. Vol. 2, pp. 154-155. JAHN, H. 1942. Zur Oekologie und Biologic der Vogel Japans. Journ. Orn. 90, 1-2 : 7-301. LA TOUCHE, J. D. D. 1934. -A handbook of the birds of Eastern China. Vol. 2, p. 209. London. KURODA, N. 1925. A contribution to the knowledge of the avifauna of the Riu Kiu Islands and the vicinity. Tokyo. MACKWORTH PRAED, C. W. & GRANT, C. H. B. 1952. The African handbook of Birds : Ser. i, vol. i, p. 468. MAYR, E. 1931. The birds of Malaita Island. Amer. Mus. Novit. 504, No. nth, 1931, p. 10. 1934- Notes on some birds from New Britain, Bismarck Archipelago. Ibid. 709, 4th April, 1934. PP- 4-5- MEADE- WALDO, E. G. 1889. Notes on some birds of the Canary Islands. Ibis, 6th Ser. No. i, pp. 6-9 and No. 4, pp. 509-510. MICULICZ-RADECKI, M. VON. 1949. Betrachtungen zur Stammesgeschichte der Wildtauben. Verhand. Deutsch. Zool., Aug. 1949, pp. 55-66. NEWMAN, T. H. 1910. Nesting of the White-throated Pigeon. Avic. Mag. 3rd Ser., vol. i, No. 5, pp. 158-164 and 193-195. 1911. The Snow Pigeon. Ibid. Vol. 2, No. 6, pp. 173-178. PETERS, J. L. 1937. Check-list of the Birds of the World. Vol. 3. Camb. Mass. U.S.A. POLLEN, P. L. & VAN DAM, D. C. 1868. Recherches sur la Faune de Madagascar et ser Dependences. Vol. 2, pp. 112-113. Leiden. SALVADORI, T. 1893. Catalogue of Birds in the British Museum. Vol. 21. SCHAFER, E. 1938. Ornithologische Ergebnisse zweier Forschungsreisen nach Tibet. Journ. f. Orn. Supplement, May 1938. SCHAUNSEE, R. M. DE. 1948. The Birds of the Republic of Columbia, part i. Bogota. SIBLEY, C. G. 1957. The evolutionary and taxonomic significance of sexual dimorphism and hybridisation in birds. Condor 59 : 3 : pp. 166-191. TAIBELL, A. M. 1954. Notizie sulla riproduzione in cattivat& del Colombo dal collare bianco (Columba albitorques}. Rivista It. Orn., 1954 (Seconda serie), pp. 195-203. VAN SOMEREN, V. G. L. 1949. The birds of Bwamba. Special supplement to the Uganda Journal, Vol. 13, pp. 24-25. VERHEYEN, R. 1955. Le Pigeon Bleu (Columba arquatrix Temm.) du Ruwenzori. Le Gerfaut, 1955. vol. 2, pp. 127-145. 1957. Analyse du potential morphologique et project de classification des columbiformes (Wetmore, 1934). Bui. Inst. Roy. Sci. Bel. Vol. 33, No. 3. WARNER, D. W. 1949. The White-throated Pigeon nesting on the ground in New Caledonia. Auk. 66 : 90-91. WETMORE, A. 1927. The birds of Porto Rico, pp. 390-391. WETMORE, A. & SWALES, B. H. 1931. The birds of Haiti and the Dominican Republic. U.S. Nat. Mus. Bull. 155 : 184. WHITMAN, C. O. 1919. The behaviour of pigeons. Posthumous works of C. O. Whitman. Vol. 3 : pp. 56-57. Carnegie Inst., Wash. ZOOL. 6, i. . r A REVISION OF THE PLATYSEIINAE (MESOSTIGMATA : ACEOSEJIDAE) BASED ON MATERIAL IN THE COLLECTIONS OF THE BRITISH MUSEUM (NATURAL HISTORY) G. OWEN EVANS and K. H. HYATT BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) ZOOLOGY Vol. 6 No. 2 LONDON: 1960 A REVISION OF THE PLATYSEIINAE (MESOSTIGMATA : ACEOSEJIDAE) BASED ON MATERIAL IN THE COLLECTIONS OF THE BRITISH MUSEUM (NATURAL HISTORY) BY G. OWEN EVANS and K. H. HYATT Department of Zoology, British Museum (Natural History) Pp. 25-101, 204 Text-figures BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) ZOOLOGY Vol. 6, No. 2 LONDON: 1960 THE BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY), instituted in 1949, is issued in five series corresponding to the Departments of the Museum, and an Historical Series. Parts will appear at irregular intervals as they become ready. Volumes will contain about three or four hundred pages, and will not necessarily be completed within one calendar year. This paper is Vol. 6, No. 2 of the Zoological series. Trustees of the British Museum, 1960 PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM Issued February, 1960 Price Twenty-four Shillings A REVISION OF THE PLATYSEIINAE (MESOSTIGMATA: ACEOSEJIDAE) BASED ON MATERIAL IN THE COLLECTIONS OF THE BRITISH MUSEUM (NATURAL HISTORY) By G. OWEN EVANS & K. H. HYATT CONTENTS INTRODUCTION EXTERNAL MORPHOLOGY CLASSIFICATION . Genus Platyseius Berlese Genus Plesiosejus gen. nov. Genus Sejus C. L. Koch Genus Zerconopsis Hull . SUMMARY .... REFERENCES Page 27 28 33 34 42 49 9i 100 IOO INTRODUCTION THE family Aceosejidae is divided into two subfamilies, Aceosejinae and the Platy- seiinae, on the basis of the chaetotaxy of the gnathosoma and the tarsi of legs II-IV (Evans, 1957). The classification of the Aceosejinae has been outlined by Evans (1958) but no revisionary work has yet been undertaken on the Platyseiinae which, at present, contains six genera, namely, Sejus C. L. Koch, 1843, Cheiroseius Berlese, 1916, Platyseius Berlese, 1916, Episeius Hull, 1918, Zerconopsis Hull, 1918, and Episeiella Willmann, 1938. Koch (1836) originally assigned a number of species to the genus Sejus but did not designate the type species of the genus, Sejus viduus C. L. Koch, until 1843. Berlese (1892) accepted Koch's wide concept of the genus and in 1913 proposed the family Seiidae for its reception together with eight other genera. Later in 1916, the same author revised his concept of the Seiidae and stated that Seius (= Sejus}, with Sejus togatus C. L. Koch as the type, was not confamilial with the other genera he had included in the family in 1913. Thus, the family Seiidae was reserved for those species having the general characteristics of Sejus togatus. Subsequent workers (Vitzthum and Tragardh) accepted Berlese's definition of Sejus and the family became established in the literature until 1936 when Oudemans noted the error in considering 5. togatus to be the type of Sejus. Consequently Sejus Berlese nee Koch became a synonym of Liroaspis Banks in spite of Tragardh's remark that " this incident offers yet another strong argument in favour of establishing nomina conservanda" (Tragardh, 1946). We are following Sellnick (see Willmann, 1953) ZOOL, 6. NO. 2. 3 28 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) who considers Epicrius corniger Berlese (1891) to be a synonym of Sejus viduus C. L. Koch. According to our generic concept Cheiroseius, Episeius and Episeiella are synonymous with Sejus. The present revision of the Platyseiinae is based on material in the Collections of the British Museum (Natural History). The major collections were made by the late A. H. G. Alston (Indonesia), P. F. Bellinger (Jamaica), Miss T. Clay (Sikkim), G. Owen Evans (Uganda), K. H. Hyatt (Nepal), P. Wygodzynsky (Argentina) and M. E. Bacchus, P. N. Lawrence and J. T. Salmon (British Isles). The type material, unless otherwise stated, is deposited in the British Museum (Natural History). EXTERNAL MORPHOLOGY Gnathosoma The chelicerae are chelate-dentate in all postembryonic developmental stages and show a marked uniformity in shape and dentition throughout the subfamily. The 1 2 3 FIG. 1-3. Chaetotaxy of the venter of the gnathosoma and palptrochanter, femur and genu in the larva (i), protonymph (2), and deutonymph (3) of Plesiosejus italicus (Berlese). i, rostral setae ; 2, external posterior rostral setae ; 3, internal posterior rostral setae ; 4, capitular setae ; n2, setae appearing in the deutonymph. THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 29 8 FIGS. 4-9. Sejus necorniger (Ouderaans), dorsum of larva (4), protonymph (5), and deutonymph (6). Plesiosejus italicus (Berlese), dorsura of larva (7), protonymph (8), and deutonymph (9). 30 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) spermatophoral process on the movable digit in the male shows considerable inter- specific variation in form (e.g. Text-figs. 33 and 41) and appears to be a useful taxonomic character. In all stages the processes from the arthrodial membrane at the base of the movable digit are simple and setiform. The postembryonic development of the chaetotaxy of the venter of the gnathosoma and of the three basal movable segments of the pedipalp is typically parasitoid (Text-figs. 1-3). The rostral setae (i) in the immature stages and in the adults are long and usually whip-like as are the internal palptrochanter setae which appear in the deutonymph. (This characteristic structure of these two pairs of setae is a useful character for separating the platyseiines from the closely related aceosejines). The corniculi are simple and the specialized seta at the inner basal angle of the palptarsus is two pronged. With the exception of Sejus dayi sp. nov., the tectum is basically tridentate with the processes subequal in length and inconspicuously divided distally (Text-figs. 28, 32 and 76). In 5. dayi the median process is extremely long and Y- shaped with the lateral processes relatively shorter (Text-fig. 117). Idiosoma The idiosoma is usually elongate-oval in outline although in Platyseius it may be subcircular. Dor sum : the dorsum of the larva has two weakly sclerotized shields. In Sejus and Plesiosejus the anterior shield bears nine pairs of setae and the pygidial four pairs 1 (Text-figs. 4 arid 7). The striated cuticle between these sclerotized areas carries two pairs of J setae (Ji and J2), three pairs of Z setae (Zi-Z3) and one pair of S setae (? 83). Three or more platelets are also present on the cuticle. We have seen three main types of protonymph which chiefly differ in the chaetotaxy of the posterior half of the dorsum. All have an anterior shield with eleven or twelve pairs of setae and a pygidial shield. In the Sejus-type (Text-fig. 5) there are five pairs of setae in the J series ; Ji and J2 being situated on the cuticle between the anterior and pygidial shields. The protonymphs of both Platyseius and Plesioseius, on the other hand show a deficiency in the chaetotaxy of the J series. The former have only two pairs in the J series (J4 and J5) and the latter three pairs (J3-J5). There are no setae of the J series present on the cuticle between the anterior and pygidial shields in these genera (Text-fig. 8). All the deutonymphs we have examined have a laterally incised dorsal shield which almost entirely covers the dorsum of the mite. The chaetotaxy of the " anterior dorsal shield " (the region anterior to the incisions) is relatively constant but the number of setae on the "posterior shield" which is largely determined in the protonymph shows con- siderable variation. Four types may be readily recognized : i. Sejus-type : J, Z and S series each with five pairs of setae (Text-fig. 6). 1 The system of nomenclature for the dorsal chaetotaxy follows that proposed by Sellnick (1944) and added to by Hirschmann (1957). The latter author has used one system of nomenclature throughout the suborder and by so doing has attempted to homologize setae in widely differing groups. This may be possible in the larval stage but becomes increasingly difficult and purely subjective in subsequent developmental stages because of the increased number of setae, especially in those forms exhibiting hypertrichy. THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 31 2. Zerconop sis-type : J and Z series each with five pairs, S series with four pairs. 3. Platyseius-type : J series with two pairs (J4 and J5), Z and S series each with five pairs. 4. Plesiosejus-type : J series with three pairs (J3-J5), Z and S series each with five pairs (Text-fig. 9). The dorsal shield in the adults is entire except in 5. clayi, Zerconopsis labradorensis sp. nov. and Zerconopsis muestari (Schweizer) which retain the deutonymphal incisions and Sejus ornatus sp. nov. which has wide incisions between 82 and 83 (Text-fig. 168). The chaetotaxy of the " posterior dorsal shield " is essentially the same as in the deutonymph so that the above four groups may also be recognized in the adult. The surface of the shield is invariably reticulated and the majority FIGS. lo-n. 10 Dorsal shield of Plesiosejus italicus (Berlese). transverse section. Fig. 10, lateral view. Fig. n, of the species have a median longitudinal ridge (Text-figs. 10 and n). The position of the highest point along this ridge varies throughout the group. It is usually located in the region of setae I4-J2 but in some species it may appear as a distinct tubercle between J4 and J5. The extreme attenuation of the posterior margin of the anterior shield in the protonymph of Plesiosejus italicus (Berl.) may be due to the development of the median ridge (cf. Text-figs. 8 and 36). Venter : The tritosternum is well developed in all stages and in the adult comprises a long slender base and a pair of strongly pilose laciniae. Pre-endopodal shields may be present in some species. The development of the chaetotaxy of the intercoxal region is normal ; the larva having three pairs (homologous with sternal setae I-III in the adult), the proto- nymph four pairs (homologous with sternal setae I-III and the genital setae in the adult) and the deutonymph five pairs (the extra setae appearing at this stage being homologous with the metasternals in the adult). The female has a strongly sclero- tized sternal shield bearing three pairs of setae and the metasternals are normally situated on discrete platelets. The genital shield is wedge shaped and except in S. clayi and certain species of Zerconopsis has a pair of setae. A sterniti-genital shield is always present in the 32 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) male although it may show various degrees of fusion with the ventral shield. The genital orifice in this sex is located near the anterior margin of the sterniti-genital. The larva has an anal shield usually with a seta on each anal valve in addition to the normal three setae present on the shield. There is a tendency for increased scJtrotization of the anal region in subsequent developmental stages so that the protonymph and the deutonymph may have a ventri-anal shield (an anal shield with usually one pair of preanals). All the females of the platyseiines we have examined have a ventri-anal shield with from one to four pairs of pre-anals. Mem- bers of the genus Platyseius in addition have two or more pairs of setae situated in the posterior half of the shield (Text-fig. 23). The ventri-anal shield in the male shows varying degrees of fusion with the sterniti-genital shield and with the dorsal shield (Text-figs. 19 and 31). FIGS. 12-14. Tarsi of leg I showing development of ambulacra. Fig. 12, Sejus viduus C. L. Koch. Fig. 13, Sejus laelaptoides (Berlese). Fig. 14, Sejus unguiculatus (Berlese). The larva lacks stigmata and peritremes but the protonymph has a pair of stigmata located ventro-laterally between coxae III and IV and short peritremes. In the deutonymph, the peritremes are well developed and extend beyond the anterior margin of coxae I. The peritrematal shields at this stage, however, are weak and inconspicuous. The adults have large peritrematal shields ; these are invariably fused with the expodals and extend posterior to coxae IV (Text-fig. 16). Many species have a strong poststigmatic prolongation of the peritreme. Legs : All the legs are usually long and slender. The structures of taxonomic importance are the form of the ambulacrum and the chaetotaxy of tarsi II-IV. The ambulacrum of leg I shows varying degrees of development. In a few species it is lacking (Text-fig. 12) but generally it comprises a lobate pulvillus and two claws. The claws may be minute or relatively large and conspicuous (Text-fig. 13). A short pretarsus is usually present ; a notable exception being Sejus unguiculatus (Berl.) in which the large claws on tarsus I are sessile (Text-fig. 14). The ambulacra THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 33 of legs II-IV are well developed and each consists of a pair of claws and a lobate pulvillus. In the majority of the platyseiines, the median and lateral lobes of the pulvilli are slender and markedly acute a probable adaptation for movement over a moist substratum. Tarsi II and III and usually IV have a pair of characteristic lanceolate setae (Text-fig. 18). Leg II in the male is never crassate or armed with spurs. CLASSIFICATION The characters previously used in separating the genera of the Platyseiinae, e.g. the outline of the idiosoma, the presence or absence of an ambulacrum on tarsus I and the form of the peritreme, are undoubtedly of some value in the practical classification of the subfamily but have no phylogenetic basis. We have concluded from our investigations of the external morphology of the group that the chaetotaxy and form of the dorsal shield in the adult and immature stages afford the most satisfactory characters for a natural classification. It is interesting to note that the variation in the form and in the chaetotaxy of the dorsal shield already noted for the Aceosejinae (Evans, 1958) is also evident in the Platyseiinae. Thus, there is a tendency towards the reduction in the number of the J and S setae on the " posterior dorsal shield " and towards the retention of the deutonymphal incisions. Our generic concept has as its basis the chaetotaxy of the " posterior dorsal shield " which has been discussed above. Subfamily PLATYSEIINAE Platyseiinae Evans, G. O., (1957), / Linn. Soc. Land. (Zool.), 43 : 244. Aceosejids with the rostral and internal palptrochanter setae long and usually whip-like. Tarsi II and III with a pair of long lanceolate setae about the middle of the segment (Text-fig. 18). Dorsal shield in the adults entire, rarely with lateral incisions. " Posterior dorsal shield" normally with fifteen pairs of setae; when fewer setae are present the J series or S series comprises less than five pairs. Females with sternal shield bearing three pairs of setae, a wedge-shaped genital shield with or without a pair of setae and a ventri-anal shield with one or more pairs of preanals. Male with sterniti-genital and ventri-anal shields, the latter often being partially fused with the dorsal shield. Both sexes with or without poststigmatic prolongation of the peritreme. Chelicerae chelate-dentate in both sexes ; movable digit with spermatophoral process in the male. Tectum basically three pronged. All legs usually slender ; leg I with or without ambulacrum, legs II-IV with pulvilli (often acutely lobate) and two claws. Leg II unarmed in the male. KEY TO GENERA ADULTS i. " Posterior dorsal shield " with 5 pairs of setae in the J series (Text-fig. 53) . " Posterior dorsal shield " with only 2 or 3 pairs of setae in the J series (Text-figs. 15 and 36) .,,,,,,, i .... 34 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 2. " Posterior dorsal shield " with 5 pairs of setae in the S series (Text-fig. 53) ; dorsum never with paddle-like setae ; peritreme often with a strong poststigmatic process (Text-fig. 54) ; median lobes of the pulvilli of ambulacra II-IV usually acuminate (Text-fig. 58) Sejus C. L. Koch (p. 49) " Posterior dorsal shield " with 4 pairs of setae in the S series, ? 82 situated on the lateral integument (Text-fig. 179) ; dorsal shield with three or more pairs of paddle-like setae, remainder of dorsal setae simple (Text-fig. 184) ; peritreme without poststigmatic prolongation ; median lobes of the pulvilli of legs II-IV rounded apically (Text-fig. 202) . . . . Zerconopsis Hull (p. 91) 3. Both sexes with three pairs of setae in the J series (Text-fig. 36) ; idiosoma elongate- oval in outline ; ventri-anal shield in the female with 3 or 4 pairs of setae in addition to the paranal and postanal setae . . . Plesiosejus gen. nov. (p. 42) Both sexes with only 2 pairs of setae in the J series (J4 and Js) ; idiosoma usually subcircular in outline (Text-fig. 15) ; ventri-anal shield in the female with 5 or 6 pairs of setae in addition to paranal and postanal setae . Platyseius Berlese (p. 34) Genus PLATYSEIUS Berlese Platyseius Berlese, A., (1916). Redia, 12 : 42. Platyseiine mites with the idiosoma usually subcircular in outline. Dorsal shield entire : " posterior dorsal shield " with J series comprising two pairs of setae (J4 and J5). Dorsal setae, with the exception of J5 in some species, long and simple. Sternal shield in the female with three pairs of setae ; metasternals situated on small plates. Genital shield wedge-shaped and with a pair of setae. Ventri-anal shield large and bearing 13 or 15 setae. Poststigmatic process of peritreme and peritrematal shield well developed and extending posterior to coxa IV. Male with sterniti-genital and ventri-anal shield, and ventri-anal shield showing varying degrees of fusion with the dorsal shield. Chaetotaxy of gnathosoma normal. Chelicerae chelate-dentate ; movable digit with spermatophoral process in the male. Tectum basically trispinate. All legs with ambulacra ; pulvilli of ambulacra II-IV acuminate. Type species Lasioseius (Platyseius) capillatus Berlese, 1916 (=Hypoaspis subglabra Oudemans, 1902) KEY TO SPECIES FEMALES Setae 15 shorter than J4 (Text-fig. 15) ; ventri-anal shield with 13 setae ; pre- endopodal shields present. Europe . . . ^ P. subglaber (Oudms.) (p. 35) Setae i5 at least twice the length of J4 (Text-fig. 22) . . . . . 2 Ventri-anal shield with 15 setae (Text-fig. 27) ; pre-endopodal shields absent. Jamaica ........ P. jamaicensis sp. nov. (p. 39) Ventri-anal shield with 13 pairs of setae (Text-fig. 23) ; pre-endopodal shields present ............. 3 Setae on ventri-anal shield simple (Text-fig. 23) ; setae J5 thorn-like, smooth. Indonesia ......... P. mollicomus Berl. (p. 37) Two pairs of setae on the posterior half of the ventri-anal shield stout, spinose (Text-fig. 35) ; setae J$ short, brush-like. East Africa P- spinosus sp. nov. (p. 41) THE PLATYSEIINAE (MESOSTIGMAT A : ACEOSEJIDAE) Platyseius subglaber (Oudemans), 1903 35 Hypoaspis subglabra Oudemans, A. C., (1903). Ent. Ber., 1 : 87 ; Abh. nat. Ver. Bremen, 18 : 88. Lasioseius (Platyseius) capillatus Berlese, A., (1916). Redia, 12 : 43, syn. nov. Lasioseius (Platyseius) subglaber, Halbert, J. N., (1923). /. Linn. Soc. Lond. (Zool.), 35 : 373. Lasiosei^is (?) listrophorus Schweizer, J., (1924). Arch fur Hydrobiol., 15: 131. FEMALE. Dorsal shield (560 ju- x 361-477 ju,) broadly oval ; ornamentation restricted to a number of small punctate areas. " Anterior dorsal shield " with FIGS. 15-18. Platyseius subglaber (Oudemans), female. Fig. 15, dorsum. Fig. 16, venter. Fig. 17, chelicera. Fig. 18, tarsus II. nineteen pairs of simple setae ; verticals very fine and short (Text-fig. 15). " Posterior dorsal shield " with twelve pairs of setae ; Ji-j3 being absent. Setae J5 short, palmate. The distribution and relative lengths of the setae on the dorsal shield and lateral interscutal membrane are shown in the figure. 36 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) Tritosternum large with a pair of strongly-pilose laciniae, and flanked at its base by two pairs of pre-endopodal shields. Sternal shield smooth and with three pairs of simple setae (Text-fig. 16). Genital shield wedge shaped and with a pair of setae. Ventri-anal shield wider than long (202-215 /i long X 280-360 IJL wide), reticulated in its anterior half and bearing thirteen setae. Six small sclerotized plates are situated between the genital and ventri-anal shields. Stigma situated FIGS. 19-21. Platyseius subglaber (Oudemans), male. Fig. 19, venter. Fig. 21, tarsus II. Fig. 20, chelicera. between coxae III and IV ; peritreme extending posterior to the stigma ; peri- trematal shield strongly developed. Metapodal shields apparently fused with the peritrematal shields. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip-like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. Dentition of chelicerae as in Text-fig. 17. THE PLATYSEIINAE (MESOSTI GM AT A : ACEOSEJIDAE) 37 Leg I (670-772 fi long) with the tarsus (160-177 /*) considerably longer than the tibia (126-140 //). Setae on tibia and tarsus fine, those on remaining segments stouter. Tarsi II-IV with a pair of long lanceolate setae. Ambulacrum of tarsus I short and claws small. Pulvilli of ambulacra II-IV produced into three long acuminate lobes (Text-fig. 18). MALE. Dorsal shield (425-467 p X 340-371 /*) is similar to that of the female. " Anterior dorsal shield " with nineteen pairs of simple setae and " posterior dorsal shield " with twelve pairs of setae. The tritosternum is flanked at its base by two or three pairs of small pre-endopodal shields. The remainder of the chaetotaxy and sclerotization of the venter is shown in Text-fig. 19. The gnathosoma and tectum are similar to those of the female. The sperma- tophoral process is about three times as long as the movable digit of the chelicera. The dentition of the chelicera, and the spermatophoral process are shown in Text- fig. 20. Leg I (602-682 /* long) has the tarsus (147-177 /*) considerably longer than the tibia (114-126 fi). The chaetotaxy of the legs is as in the female. The ambulacra of tarsi II-IV are provided with lanceolate pulvilli (Text-fig. 21). DISTRIBUTION. This species is widely distributed in western Europe. In Great Britain we have examined specimens from Cumber Park, Nottinghamshire (coll. G. O. E., April, 1955), Dungeness, Kent (coll. D. A. Chant, July, 1955), Box Hill, Surrey (coll. E. Duffey, 30. vi. 1951), and St. Agnes, Isles of Stilly (coll. K. H. H., September, 1957). Platyseius mollicomus Berlese, 1916 Lasioseius (Platyseius} mollicomus Berlese, A., (1916). Redia, 12 : 43. Platyseius mollicomus, Vitzthum, H. G., (1931). Arch, fur Hydrobiol., Suppl., 9 : 70, figs. FEMALE. Dorsal shield (570-580 ju, X 467-480 /*) broadly oval in outline ; ornamentation restricted to a number of faint reticulated areas. " Anterior dorsal shield " with twenty-one pairs of simple setae (Text-fig. 22). " Posterior dorsal shield " with twelve pairs of simple setae ; Ji-Js being absent. Setae J5 are short and simple. The distribution and relative lengths of the setae on the dorsal shield are shown in the Text-fig. Tritosternum large with a pair of strongly pilose laciniae, and flanked at its base by two pairs of pre-endopodal shields. Sternal shield with three pairs of simple setae and faintly reticulated (Text-fig. 23). Genital shield slightly convex pos- teriorly and with a pair of setae. Ventri-anal shield wider than long (177 // long X 318 IL wide) with a transverse line anteriorly, and bearing thirteen setae. Four small sclerotized plates are situated between the genital and ventri-anal shields. Stigma situated between coxae III and IV. Peritreme broad, occupying most of the peritrematal shield, and with two deep indentations (Text-fig. 24), and extending posterior to the stigma. Metapodal shields fused with the peritrematal shields. Venter of gnathosoma with rostral and internal palptrochanter setae long and 38 THE PLATYSEIINAE (MESOSTI GM AT A : ACEOSEJIDAE) whip-like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The chelicerae are typical. Leg I (700-760 fi long) with the tarsus (202 fi) longer than the tibia (126 //). Setae on tarsus fine, those on remaining segments stouter. Tarsi II-IV with a pair of long lanceolate setae. Ambulacrum of tarsus I fairly short and claws small. Pulvilli of ambulacra II-IV produced into three acuminate lobes (Text-fig. 25). FIGS. 22-25. Platyseius mollicomus Berlese, female. Fig. 22, dorsum. Fig. 23, venter. Fig. 24, peritrematal shield. Fig. 25, tarsus II. MALE. This sex (415 /i x 340 ju,) is described by Vitzthum (1931) who also gives a figure of the chelicera. DISTRIBUTION. Berlese (1916) based his description on material collected in Java by Cl. Jacobson. Vitzthum (1931) examined specimens (male, female and deutonymph) from Tjibodas, Java (Indonesia). The Museum Collections contain a female and a deutonymph collected by A. H. G. Alston in decaying leaves and THE PLATYSEIINAE (MESOSTIGMATA : ACEOSEJIDAE) 39 fruit, Bogor, Indonesia (1956.2.27.6) ; and a single female collected by G. Owen Evans in grassland nine miles north-east of Bundibugyo, Ruwenzori, Uganda, 24.viii.i952 (1959.1.20.1). Platyseius jamaicensis sp. nov. FEMALE. Dorsal shield (498 ju, x 392-402 /*) broadly oval in outline ; ornamenta- tion restricted to a number of small punctate areas. "Anterior dorsal shield" with twenty pairs of simple setae of which the verticals are the shortest (Text-fig. 30 FIGS. 26-30 Platyseius jamaicensis sp. nov., female. Fig. 26, dorsum. Fig. 27, venter. Fig. 28, tectum. Fig. 29, chelicera. Fig. 30, tarsus II. 26). " Posterior dorsal shield " with thirteen pairs of setae ; Ji-j3 being absent. Setae J5 short, palmate and inconspicuous. J4 and Z5 are stout. The distribution and relative lengths of the setae on the dorsal shield are shown in the Text-fig. Tritosternum large with a pair of strongly-pilose laciniae. Sternal shield with a pair of longitudinal elongate punctate areas and three pairs of simple setae (Text- fig. 27). Genital shield convex posteriorly and finely reticulated, with a pair of setae. Ventri-anal shield wider than long (152 /i long X 253-273 p wide), reticulated 40 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) anteriorly and bearing fifteen setae. Four small sclerotized plates are situated between the genital and ventri-anal shields. Stigma situated between coxae III and IV, peritreme extending posterior to the stigma ; peritrematal shield strongly developed. Metapodal shields apparently fused with the peritrematal shields. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip-like. All setae on pedipalp simple. Tectum (Text-fig. 28) three-pronged FIGS. 31-33. Platyseius jamaicensis sp. nov., male. Fig. 31, venter. Fig. 32, tectum. Fig. 33, chelicera. and typical of the genus. Dentition of chelicera as in Text-fig. 29. Leg I (about 770 /i long) with the tarsus (177 p] longer than the tibia (157 /*). Setae on tibia and tarsus very fine : those on remaining segments stouter. Tarsi II-IV with a pair of long lanceolate setae. Ambulacrum of tarsus I short and the claws small. Pulvilli of ambulacra II-IV produced into three acuminate lobes (Text-fig. 30). THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 41 MALE. Dorsal shield (498 /i x 310 ft) similar to that of the female. The tri- tosternum is of the same form as in the female. The chaetotaxy and sclerotization of the venter are shown in Text-fig. 31. The gnathosoma is similar to that of the female, and the tectum is shown in Text-fig. 32. The spermatophoral process is about twice as long as the movable digit of the chelicera (Text-fig. 33). Leg I (c. 680 ft) with the tarsus and tibia each 152 ft. The chaetotaxy and ambulacra of the legs are as in the female. LOCALITY. Jamaica, B.W.I. The holotype female (1959.1.20.18) and one paratype from Fairy Glade, St. Andrew, in Lycopodium, 4,300 ft., 6.xii.i956; and the allotype male (1959.1.20.19) from St. Thomas, John Cove Mountains, in moss, 2,300 ft., 25. v. 1956 collected by P. F. Bellinger. The paratype female has been returned to the collector. Platyseius spinosus sp. nov. FEMALE. Dorsal shield (498 /* x 402 (JL) broadly oval in outline ; ornamentation restricted to a number of very faint reticulated areas. " Anterior dorsal shield " FIGS. 34-35. Platyseius spinosus sp. nov., female. Fig. 34, dorsal shield. Fig. 35, venter. with twenty-one pairs of simple setae (Text-fig. 34). Posterior dorsal shield with thirteen pairs of simple setae ; Ji-Js being absent. Setae J5 are short, palmate and inconspicuous. Z5 are stout. The distribution and relative lengths of the setae on the dorsal shield are shown in the Text-fig. \ ZOOL. 6, NO. 2. 42 THE PLATYSEIINAE (MESOSTIGMAT A : ACEOSEJIDAE) Tritosternum large with a pair of strongly-pilose laciniae, and flanked at its base by one or two pairs of pre-endopodal shields. Sternal shield with three pairs of simple setae and with a characteristically-shaped central mark (Text-fig. 35). Genital shield slightly convex posteriorly and with a pair of setae. Ventri-anal shield wider than long (177 p long x 298 p wide) with a transverse line anteriorly and bearing thirteen setae of which two pairs are stout. A narrow sclerotized band and two narrow plates are situated between the genital and ventri-anal shields. Stigma situated between coxae III and IV, peritreme broad, occupying most of the peritrematal shield, with a deep indentation, and extending posterior to the stigma. Metapodal shields fused with the peritrematal shields. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The chelicerae are typical. Leg I (707 /* long) with the tarsus (202 fi) longer than the tibia (126 fi). Setae on tarsus fine ; those on remaining segments stouter. Tarsi II-IV with a pair of long lanceolate setae. Ambulacrum of tarsus I short and claws small. Pulvilli of ambulacra II-IV produced into three acuminate lobes. MALE. Unknown. LOCALITY. Ruwenzori, Uganda. A single female (1959.1.20.20), collected by G. Owen Evans, in grassland at 2,850 ft., 24.viii.i952, nine miles north-east of Bundibugyo. Genus PLESIOSEJUS gen. nov. Platyseiine mites with the " posterior dorsal shield " having only three pairs of setae in the J series (Ji and J2 absent). Z and J series each with five pairs. Lateral margins of the dorsal shield entire in the adult stages. Vertical setae present or absent. Sternal shield in the female with three pairs of simple setae ; metasternals free. Genital shield wedge-shaped and bearing a pair of setae. Ventri-anal shield large with three or four pairs of setae in addition to the paranals and the postanal seta. Male with sterniti-genital and ventri-anal shields, the latter showing varying degrees of fusion with the podal-peritrematal and dorsal shields. Type species Ameroseius it aliens Berlese, 1905 KEY TO SPECIES FEMALES Without poststigmatic prolongation of peritreme (Text-fig. 50) ; majority of dorsal setae long, stout (Text-fig. 49) ; vertical setae well developed, directed anteriorly ; ventri-anal shield with 9 setae. Jamaica . . P. horridus sp. nov. (p. 48) With strong poststigmatic prolongation of peritreme extending posterior to coxa IV ; dorsal setae considerably shorter (Text-fig. 36) ; vertical setae absent ; ventri-anal shield with 1 1 setae ......... 2 Dorsal shield with distinct " tubercle " posterior to J4 (Text-fig. 36). Europe P. italicus (Berlese), (p. 43) Dorsal shield without such " tubercle " (Text-fig. 42). P. major (Halbert), (p. 47) THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 43 Plesiosejus italicus (Berlese), comb. nov. Ameroseius italicus Berlese, A., (1905). Redia, 2 : 234 ; (1906). Ibid., 6 : tav. 19, Text-figs. 35. 35a. Paraseius tenuipes Halbert, J. N. (1915). Proc. R. Irish Acad., 39ii : 78, syn. nov. Lasioseius italicus Berlese, A., (1916). Redia, 12 : 34. i Lasioseius (Episeius) michaeli Halbert, J. N., (1923). /. Linn. Soc. Lond. (Zool.), 35 : 373. Episeius tenuipes, Schweizer, J., (1949). Res. Rech. sci. Pare Nat. Suisse, N.F. 2 : 60. E. tenuipes, Franz, H., (1943). Denkschr. Akad. Wiss. Wien., 107 : 87. FEMALE. Dorsal shield (550-651 p long x 310-402 ju, wide) oval; ornamentation comprising a reticulated pattern covering the whole shield (Text-fig. 36). " Anterior dorsal shield " with twenty pairs of simple setae ; verticals absent. " Posterior dorsal shield" with thirteen pairs of setae; Ji-j2 being absent; J5 are finely pilose. A strong tubercle arising posterior to setae J3 denotes the highest point on the median ridge of the dorsal shield. The distribution and relative lengths of the setae and the structure of the dorsal shield are shown in the Text-fig. Tritosternum well developed with pilose laciniae, and flanked at its base by one or two pairs of small pre-endopodal shields. Sternal shield with three pairs of simple setae and two oval areas antero-medially (Text-fig. 37). Genital shield convex posteriorly, and bearing one pair of setae. Ventri-anal shield considerably wider than long (177-202 /* long X 265-341 ft, wide), reticulated and bearing eleven simple setae. Between the genital and ventri-anal shields lie six narrow sclerotized plates. Stigma between coxae III and IV and the peritreme extending posterior to coxa IV ; peritrematal shield strongly sclerotized. Metapodal shields free and transversely situated. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 38. Leg I (639-726 ft long) with the tarsus (167-195 ju) longer than the tibia (113- 129 fi). Setae on tarsus and tibia very fine ; those on remaining segments stouter ; ambulacra short and claws small. Tarsi II-IV with a pair of lanceolate setae ; pulvilli produced into three acuminate lobes (Text-fig. 39). MALE. Dorsal shield (467-507 ju, long x 279-310 fi wide) entirely reticulated as in the female. "Anterior dorsal shield" with nineteen pairs of simple setae, verticals absent. " Posterior dorsal shield " with thirteen pairs of setae ; Ji-Js absent ; J5 short and pilose. Postero-dorsal tubercle not so pronounced as in the female. Tritosternum as in the female. The chaetotaxy and sclerotization of the venter are shown in Text-fig. 40. The gnathosoma and tectum are similar to those of the female. Spermatophoral process four times as long as the movable digit of the chelicera (Text-fig. 41). Leg I (534 ju, long) with the tarsus (147-152 ft) longer than the tibia (96-106 /*). The chaetotaxy and ambulacra of the legs are similar to the female. 44 THE PLATYSEIINAE (MESOSTIGMATA : ACEOSEJIDAE) DISTRIBUTION. Berlese's (1905 and 1916) descriptions of the male and female of italicus are based on specimens collected under dead rotting leaves on a marsh at Udine in northern Italy. Halbert (1915) described P. tenuipes from a single female " found amongst moss on a stone in a mountain stream at Glencree, County Dublin, May ". Schweizer (1949) records tenuipes from the Swiss National Park. We have FIGS. 36-39. Plesiosejus italicus (Berlese), female. Fig. 36, dorsum. Fig. 37, venter. Fig. 38. chelicera. Fig. 39, tarsus II THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSE J ID AE) 45 examined British specimens from the following localities : Thirlmere, Cumberland, 25. ix. 1956, coll. P. N. Lawrence ; Grasmere, Westmorland, 29.^.1951, coll. J. T. Salmon; Blelham Tarn, Lancashire, 22.iii.i955, coll. R. J. Elliott; summit of Snowdon, Caernarvonshire, August, 1951, coll. E. Duffey ; Minworth, Birmingham, io.ix.T-952, coll. T. G. Tomlinson ; Swithland Wood and Anstey, Leicestershire, 19. iv. 1958, coll. P. N. L.; Sea Houses, Northumberland, i.x.i95i, coll. J. T. FIGS. 40-41. Plesiosejus italicus (Berlese), male. Fig. 40, venter. Fig. 41, chelicera. Salmon; Oxted, Surrey, 20. i. 1957, coll. P. N. L.; Leith Hill, Surrey, 6.vi.i95i, coll. J. T. Salmon; Keston, Kent, 2.viii.i957, coll. P. N. L. ; Dungeness, Kent, S.vii.igss, coll. D. A. Chant; Avonmouth, Gloucestershire, ii.v.1957, coll. P. N. L.; Combe Martin, Devonshire, March and June, 1957, coll. P. N. L. and M. E. Bacchus ; Forth Gwarra, Cornwall (A. D. Michael Coll.) ; The Burren, Co. Clare, 6.vi.i95i, coll. E. A. J. Duffy. 4 6 THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) FIGS. 42-47. Plesiosejus major (Halbert). Fig. 42, dorsum of female. Fig. 43, venter of female. Fig. 44, chelicera of female. Fig. 45, tarsus II of female. Fig. 46, venter of male. Fig. 47, chelicera of male. THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 47 Plesiosejus major (Halbert), comb. nov. Lasioseius (Episeius) major Halbert, J. N., (1923). /. Linn. Soc. Zool. Land. 35 : 373. Lasioseius (L.) tenuipes, Schweizer, J., (1922). Verh. Naturf. Ges. Basel, 33 : 43. Episeius major, Schweizer, J., (1949). Res. Rech. sci. Pare Nat. Suisse, N.F. 2 : 61. FEMALE. Dorsal shield (581-740 ju, long x 371-488 fi wide) broadly oval in outline : ornamentation consisting of a dense reticulated pattern covering the whole of the shield (Text-fig. 42). " Anterior dorsal shield " with twenty pairs of simple setae. " Posterior dorsal shield " with thirteen pairs of setae ; Ji-j2 being absent ; setae J5 are short and spiculate. The distribution and relative lengths of the dorsal setae are shown in the Text-fig. Tritosternum well developed with pilose laciniae, and flanked at its base by two or three pairs of small pre-endopodal shields. Sternal shield with three pairs of simple setae (Text-fig. 43). Genital shield with one pair of setae and slightly convex posteriorly. Ventri-anal shield wider than long (203-253 ju, long X 288-379 /* wide), strongly reticulated and bearing eleven simple setae. Six narrow sclerotized plates are situated transversely on the membrane between the genital and ventri-anal shields. Stigma situated between coxae III and IV with the peritreme extending posterior to coxa IV. Peritrematal shield strongly sclerotized. Metapodal shields free and obliquely situated. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 44. Leg I (681-797 /* l n g) with the tarsus (147-177 p] longer than the tibia (106- 152 fi) ; pulvillus short, claws small. Setae on tarsus and tibia very fine ; those on remaining segments stouter. Tarsi II-IV with a pair of lanceolate setae ; pulvilli produced into three acuminate lobes (Text-fig. 45). MALE. Dorsal shield (550 fi long x 340 /* wide) of the same form and chaetotaxy as the female. The structure and chaetotaxy of the venter are shown in Text-fig. 46. The gnathosoma and tectum are similar to those of the female. The sperma- tophoral process is twice as long as the movable digit of the chelicera (Text-fig. 47). Leg I (670 ju, long) with the tarsus (165 /*) longer than the tibia (126 fi}. The legs are similar to those of the female. DISTRIBUTION. Halbert's (1923) description of males and females of this species is based on specimens found in moss in streams at Kilmashogue and Glencullen in Ireland, and at Mill Bay, Land's End, England. Schweizer (1922) described what he considered to be males of Lasioseius tenuipes (Halbert) from Basel, Switzerland, but his figures show clearly that his specimens are Plesiosejus major (Halbert). In 1949 the same author recorded major from the Swiss National Park. We have examined specimens collected by the River Tolka, Glasnevin, Co. Dublin (Halbert Collection), and from the following localities: Oxted, Surrey, 20. i. 1957, coll. P. N. Lawrence ; Cumber Park, Nottinghamshire, April, 1955, coll. G. O. E. ; Markfield and Anstey, Leicestershire, 19. iv. 1958, coll. P. N. L.; Blea Tarn, West- 4 8 THE PLATYSEIINAE (MESOSTI GM AT A : ACEOSEJIDAE) morland, 27. ix. 1956, coll. P. N. L.; and Chorley, Lancashire, 21. xi. 1940, coll. Water Pollution Research Laboratory. All these British specimens were collected from wet habitats (mosses, etc.). Plesiosejus horridus sp. nov. FEMALE. Dorsal shield (350 /* long x 218 fi wide) narrower in outline than in the other species of the genus, and is steeply elevated posteriorly (Text-fig. 48). FIGS. 48-52. Plesiosejus horridus sp. nov., female. Fig. 48, lateral view of dorsum. Fig. 49, dorsal shield. Fig. 50, venter. Fig. 51, chelicera. Fig. 52, tarsus II. There is no noticeable ornamentation on the dorsal shield. " Anterior dorsal shield" with twenty pairs of setae. Ji-Js absent. Setae J5 are partly concealed by the postero-dorsal elevation of the dorsal shield which bears J4 at its apex (Text-fig. 49). The distribution and relative lengths of the dorsal setae are shown in the Text-fig. Tritosternum well developed with pilose laciniae. Sternal shield with three pairs THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 49 of short simple setae (Text-fig. 50). Genital shield flask shaped with a pair of setae. Ventri-anal shield slightly wider than long (93 fi long X 113 [i wide), with nine setae of which two lateral pairs are long. There appears to be a narrow sclerotized band between the genital and ventri-anal shields. Stigma between coxae III and IV, with the narrow, crenate peritreme not extending posterior to the stigma. Peri- trematal shield extending to the posterior margin of coxa IV. Metapodal plates oval, free. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 51. Leg I (370 (i long) with the tarsus (96 fi) one-and-a-half times as long as the tibia (63^). Setae on tarsus very fine ; those on remaining segments stouter. Tarsi II- IV with a pair of lanceolate setae. Tarsus I without claws. Pulvilli of tarsi II-IV produced into three acuminate lobes (Text-fig. 52). Leg IV 370 ju, long with the tarsus 130 fi. MALE. Unknown. LOCALITY. Jamaica, B.W.I. The holotype female (1959.1.20.41) and two paratype females (1959.1.20.42) in damp leaf litter, St. Ann, Mt. Diablo, 2,200 ft., 3.vi.i956, collected by P. F. Bellinger. One paratype has been returned to the collector. Genus SEJUS C. L. Koch Sejus Koch, C. L., (I843) 1 Ubers. d. Arachnidensyst., Heft 3 : 92. Cheiroseius Berlese, A., (1916). Redia, 12 : 33. Episeius Hull, J. E., (1918). Trans, nat. Hist. Soc. Northumb. (n.s.), 5 : 63. Episeiella Willmann, C., (1938). Ann. Hist. nat. Mus. Hung., 31 : 167. Platyseiine mites with the " posterior dorsal shield " bearing fifteen pairs of setae of which five pairs belong to the J series ; S series also comprising five pairs. Dorsal setae usually simple, rarely pilose. Lateral margins of the dorsal shield entire or incised. Sternal shield in the female with three pairs of setae ; metasternals free. Genital shield wedge shaped and bearing a pair of setae. Ventri-anal shield large with two or more pairs of pre-anals. Peritreme with or without poststigmatic process. Leg I rarely without ambulacrum, usually with at least two claws. Legs II-IV with normal ambulacrum. This is, at present, the largest genus of the subfamily. A number of the older species are inadequately described and must remain species incertae sedis until the type material can be re-examined. The following key includes only those species we have examined. Type species Sejus viduus C. L. Koch, 1839 1 PP- 73~ I 3 2 f the third Heft were published in 1843 although most authors consider the complete Heft to have appeared in 1842. 50 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) KEY TO THE SPECIES IN THE BRITISH MUSEUM (NATURAL HISTORY) FEMALES 1. Dorsal shield with lateral incisions (Text-figs. 114 and 168) .... 2 Lateral margins of the dorsal shield entire ....... 3 2. Lateral incisions located anterior to setae Si and coinciding with their position in the deutonymph (Text-fig. 114) ; median process of tectum long, Y-shaped (Text-fig. 117) ; vertical setae absent; ventri-anal shield with one pair of preanals (Text-fig. 116). Sikkim .... S. clayi sp. nov. (p. 73) Lateral incisions wide and situated between 82 and 83 (Text. -fig 168) ; median process of tectum not Y-shaped ; vertical setae present ; ventrianal shield with two pairs of preanals (Text-fig. 169). Argentina . S. ornatus sp. nov. (p. 88) 3. Tarsus I without ambulacrum (Text-fig. 12) . . . . . . 4 Tarsus I with ambulacrum or at least with two distinct claws ... 6 4. Vertical setae considerably longer than 12 (Text-fig. 53) ; poststigmatic process of the peritreme extending posterior to coxa IV (Text-fig. 54). Europe S. viduus C. L. Koch. (p. 52) Vertical setae shorter than i2 (Text-fig. 162) ; poststigmatic process very short or absent ............. 5 5. With a short but conspicuous poststimatic process of the peritreme ; sternal shield with an elongate reticulated area (Text-fig. 164). Sikkim and Argentina S. browningi sp. nov. (p. 86) Without a poststigmatic process ; sternal shield without such ornamentation (Text-fig. 144). Jamaica ...... S. hulli sp. nov. (p. 81) 6. Peritreme not produced posterior to the stigma (Text-fig. 81) or poststigmatic process narrow, short, never extending posterior to coxa IV (Text-fig. 154) . 7 Poststigmatic portion of the peritreme strongly developed and extending posterior to coxa IV (Text-fig. 56) .......... 17 7. Dorsal shield strongly arched (Text-fig. 79) ; sternal region not definitely sclero- tized (Text-fig. 81) ; a number of dorsal setae broad, pilose ; ventrianal shield with 7 setae. Britain ..... S. dromadis sp. nov. (p. 62) Dorsal shield at the most with a median longitudinal ridge ; sternal shield well- sclerotized ; dorsal setae simple or lanceolate ...... 8 8. Leg IV greatly elongated, more than twice the length of the dorsal shield (Text-fig. 99) ; vertical setae prominent, directed anteriorly ; ventri-anal shield with 9 setae. E. Africa ...... S. phalangioides sp. nov. (p. 66) Leg IV never more than i times the length of the dorsal shield ... 9 9. Vertical setae apparently absent (Text-fig. 124) ; dorsal and ventral shields charac- teristically ornamented (Text-figs. 124, 125, 129). Jamaica S. aciculatus sp. nov. (p. 76) Vertical setae present, prominent, directed anteriorly (Text-fig. 153) . . 10 10. Peritreme with a distinct poststigmatic process (Text-fig. 154) . . . . n Peritreme without a poststigmatic process (Text-fig. 141) . . . . 13 11. Dorsal shield with a distinct " tubercle " in the region of setae J4 this indicates the highest point of the median longitudinal ridge (Text-fig. 153) ; postigmatic portion of peritreme extending to about the middle of coxa IV. Jamaica 5. neborealis sp. nov. (p. 84) Dorsal shield without tubercle in the region of setae J4 . . . . . 12 12. Vertical setae shorter than J2 (Text-fig. 103) ; femur, genu and tibia of leg with sharply pointed spine-like setae situated on tubercles along their anterior and posterior margins; ventri-anal shield with 9 setae (Text-fig. 104). E. Africa 5. spinipes sp. nov. (p. 69) Vertical setae long, about equal in length to J2 (Text-fig. 63) ; chaetotaxy of leg I normal ; ventri-anal shield with n setae. Europe 5. borealis (Berl.) (p. 56) THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 51 13. Tarsus I with a long, strong seta situated dorsally towards the middle of the segment (Text-fig. 140) . . . . . . . . . . I ^ Tarsus I without such a prominent seta dorsally . . . . . . 15 14. Dorsal shield with a conspicuous tubercle overhanging setae J5 (Text-fig. 158). Jamaica . 5. nodosus sp. nov. (p. 85) Dorsal shield without a tubercle in the region of setae J4 and J5 (Text-fig. 138). Jamaica 5. bellingeri sp. nov. (p 81). 15. Ventri-anal shield broad, gently rounded posteriorly (Text-fig. 92) ; peritrematal shield not developed posterior to coxa IV. E. Africa . S. kennedyi sp. nov. (p. 65) Ventri-anal shield markedly tapering in its posterior half (Text-figs. 121 and 132), subtriangular in outline ......... 16 1 6. Sternal shield with a distinct reticulated area medially ; pre-endopodal shields absent ; paranal setae situated on a strongly-sclerotized bar (Text-fig. 132). Jamaica ........ 5. antillanus sp. nov. (p. 78) Sternal shield without reticulated area ; pre-endopodal shields present (Text- fig. 12 1) ; paranals not on sclerotized bar. Indonesia . S. alstoni sp. nov. (p. 74) 17. Claws on leg I large, sessile (Text-fig. 14) ; tarsus I with a thick spine on its anterior margin. Europe .... 5. unguiculatus (Berl.) (p. 53) Claw on leg I normal, usually situated on a pretarsus, if sessile claws minute (Text-fig. 13) . 18 18. Surface of dorsal shield minutely punctured or tuberculated (Text-fig. 55), reticula- tion when present restricted to the lateral margins of the shield . . . 19 Surface of the dorsal shield reticulated, often scabrid, without punctures (Text- fig. 74) . 20 19. Dorsal shield minutely punctured (Text-fig. 55) ; sternal shield with an oval reticulated area (Text-fig. 56) ; ventri-anal shield with n setae. Europe S. laelaptoides (Berl.) (p. 54) Dorsal shield tuberculated (Text-fig. 174) ; sternal shield lacking a reticulated area ; ventri-anal shield with 9 setae (Text-fig. 175). Argentina S. tuberculatus sp. nov. (p. 89) 20. Claws on leg I minute, apparently sessile ; leg I long and slender, about i times the length of the dorsal shield .......... 21 Claws on leg I situated on a short but distinct pretarsus ; leg I usually considerably less than ij times the length of the dorsal shield ...... 22 2 1 . Tibia and tarsus I approximately equal in length ; tarsus I more than 200/4 in length. Jamaica ........ S. jamaicensis sp. nov. (p. 83) Tibia I distinctly longer than tarsus I ; tarsus I not more than 160/1 in length. Nepal ........ S. nepalensis sp. nov. (p. 71) 22. Vertical setae long, directed anteriorly (Text-fig. 74) ; dorsal shield heavily orna- mented ; tarsus I about twice the length of tibia I. British Isles 5. cassiteridum sp. nov. (p. 61) Vertical setae relatively shorter, directed antero-laterally or posteriorly (Text- figs. 67 and 86) ; vertex not well developed ....... 23 23. Tibia I equal in length to or longer than tarsus I. Europe S. serratus (Halbert) (p. 58) Tibia I distinctly shorter than tarsus I (i : 1.3-1.7) ...... 24 24. Ventri-anal shield with five subcircular areas arranged crescentically posterior to the paranals (Text-fig. 87) ; small weakly-sclerotized species about 360^ in length. E. Africa . S. areolatus sp. nov. (p. 64) Ventri-anal shield without such areas ; larger species 400-800/4 in length . . 25 25. J5 about J the length of J4, setiform (Text- fig. no). Nepal S. parbatensis sp. nov. (p. 72) J5 less than i the length of J4, usually thorn-like ...... 26 52 THE PLATYSEIINAE (ME SOSTIGM AT A : ACEOSEJIDAE) 26. Sternal shield without semicircular depressions near its anterior margin (Text-fig. 71). Europe ........ S. curtipes (Halbert) (p. 59) Sternal shield with a pair of semicircular depressions near its anterior margin (Text-fig. 60) 27 27. Sclerotized bases of the vertical setae large, almost contiguous (Text-fig. 59) ; highest point of median dorsal ridge located between 15. Europe 5. necorniger (Oudemans) (p. 55) Bases of vertical setae weakly sclerotized, widely separated (Text-fig. 100) ; highest point of median dorsal elevation located between i5 and Ji. E. Africa S. signatus sp. nov. (p. 68) Sejus viduus C. L. Koch Sejus viduus Koch, C. L., 1839, Deutsch. Crust. Myr. Arach., Fasc. 24, t. 10. Epicrius corniger Berlese A., 1891, A. M.S., Fasc. 59, No. 2. Sejus viduus C. L. Koch, Oudemans, A. C., 1936, K.H.O.A., 3A : 376. Episeiella heteropoda Willmann, C., 1938, Ann. Hist. nat. Mus. Hung., 31 : 164, syn. nov. FEMALE. Dorsal shield (529 ju, long x 330 p wide) covered by a strong irregular 54 FIGS. 53-54. Sejus viduus (C. L. Koch), female. Fig. 53, dorsal shield. Fig. 54, venter. THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 53 network. Lateral margins irregular. "Anterior dorsal shield" with twenty-one pairs of simple setae ; verticals very prominent, well separated, and directed anteriorly. " Posterior dorsal shield " with fifteen pairs of simple setae of which J5 are the shortest. All the setae arise from small protuberances (Text-fig. 53). Tritosternum with a pair of pilose laciniae. Sternal shield with a reticulated area medially and bearing three pairs of simple setae. Genital shield slightly convex posteriorly and bearing a single pair of simple setae. Ventri-anal shield broader than long (101 /* long x 139 /* wide) with only faint traces of reticulations, and bearing nine simple setae. Between the genital and ventri-anal shields lie four narrow sclerotized platelets. Stigma situated between coxae III and IV ; posterior prolongation of peritreme, and peritrematal shield, reaching beyond the posterior margin of coxa IV (Text-fig. 54). Metapodal shields small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged, and chelicerae typical of the genus. Leg I (724 /* long) with the tarsus (144 JLI) shorter than the tibia (167 /*). Setae on tarsus, tibia and genu I very fine ; tarsal claws absent ; remaining setae stouter. Tarsi II-IV with a pair of lanceolate setae ; ambulacra without acuminate lobes. MALE. Unknown. DISTRIBUTION. Koch's (1839) description is based on material from wet woodland habitats in Germany. Berlese's (1891) description of Epicrius corniger is based on several specimens in moss on high mountains, Venice. Berlese's type has been examined by us in Florence. Willmann's (1939) description of Episeiella heteropoda, was made from one female sifted at Vihnyei volgy, Hungary, and is the specimen from which our description and figures are made. Sejus unguiculatus Berlese Sejus unguiculatus Berlese, A., 1887, A. M.S., 41, No. 4. Lasioseius (Cheiroseius) unguiculatus Berlese, A., 1916, Redia, 12 : 33. The characteristic feature of this species is that the claws on tarsus I are greatly enlarged and sessile (Text-fig. 14). The chaetotaxy of the dorsal shield is typical of the genus. The " posterior dorsal shield " bears fifteen pairs of setae ; five pairs in the J series. The " anterior dorsal shield " bears twenty pairs of setae ; vertex weakly developed. The chaetotaxy and sclerotization of the venter are typical of Sejus. Sternal shield with three pairs of setae ; genital shield with one pair of setae ; ventri-anal shield large, occupying most of the area posterior to coxae IV, and bearing eleven simple setae. Six small plates are situated between the genital and ventri-anal shields. Peritreme extending posterior to coxa IV. Metapodal plates conspicuous. Berlese described this species from moss in Venice. The above description is based on drawings of the type. This species is not represented in the Museum Collections. 54 THE PLATYSEIINAE (MESOSTIGMAT A : ACEOSEJIDAE) Sejus Ixlaptoides (Berlese) comb. nov. Epicrius laelaptoides Berlese, A., 1887, A. M.S., Fasc. 40, No. 10. Parasejus glaber var. minor Tragardh, I., 1910, Naturw. Untersuch. Sarekgeb., 4 : 432, syn. nov. Lasioseius (Episeius) sphagni Halbert, J. N., 1923, /. Linn. Soc. Lond. (Zool.), 35 : 371, syn. nov. FEMALE. Dorsal shield (518-581 /* long x 330-415 ju, wide) minutely punctured and with a few faint scattered reticulated areas (Text-fig. 55). " Anterior dorsal shield ' ' with twenty-one pairs of simple setae ; verticals well separated and directed anteriorly. " Posterior dorsal shield " with fifteen pairs of simple setae ; J5 very 56 FIGS. 55-58. Sejus laelaptoides (Berlese), female. Fig. 55, dorsum. Fig. 56, venter. Fig. 57, chelicera. Fig. 58, tarsus II. short. The distribution and relative lengths of the dorsal setae, and the ornamenta- tion of the dorsal shield are shown in the Text-fig. Tritosternum well developed with pilose laciniae. Sternal shield with a con- spicuous elliptical reticulated area, and bearing three pairs of simple setae (Text- fig. 56). Genital shield broad, posterior margin straight, and bearing one pair of simple setae. Ventri-anal shield large, broader than long (152-215 /i long x 240- 291 fi wide), reticulated, and bearing eleven simple setae. Between the genital and ventri-anal shields lies a row of four narrow sclerotized plates. Stigma situated between coxae III and IV ; peritreme and peritrematal shield extending posterior to coxa IV. Metapodal plates small. THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 55 Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 57. Leg I (536-673 IJL long) with the tarsus (113-126 f) longer than the tibia (104- 118/4). Setae on tarsus and tibia fine, those on other segments somewhat stouter ; tarsal claws strong. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes (Text-fig. 58). MALE. Unknown. DISTRIBUTION. Berlese (1887) described Epicrius laelaptoides from the Royal Botanic Gardens, Padua. Tragardh (1910) described Parasejus glaber var. minor from Sphagmim at Sarekgebirge, Sweden, and Halbert (1923) described Lasioseius (Episeius) sphagni from Sphagnum in Co. Dublin, Eire. The writers have examined Berlese's type in Florence, Halbert's type, and also numbers of females from Whern- side Moor, Cock Hill, and Malham Tarn, Yorkshire ; Rydal Water and Grasmere, Westmorland ; Leith Hill and Beckley, Surrey ; Lapland ; and Michigan. Sejus necorniger (Oudemans) comb. nov. Hypoaspis necorniger Oudemans, A. C., 1903, Ent. Ber., 1, 12 : 87. Platyseius necorniger, Buitendijk, A. M., 1945, Zool. Med., 24 : 296. Episeius necorniger, Willmann, C., 1949, Veroff. Mus. Nat. Bremen, No. lA : 120. Episeius necorniger, Willmann, C., 1952, Veroff. Inst. Meeresf. Bremerhaven, 1 : 148. FEMALE. Dorsal shield (550-722 /* long x 320-467 fi wide) completely covered by a fine reticulated pattern (Text-fig. 59). " Anterior dorsal shield " with twenty- one pairs of simple setae ; verticals, with their bases close together, considerably shorter than post- verticals. " Posterior dorsal shield " with fifteen pairs of simple setae. The distribution of the setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed with pilose laciniae. Sternal shield with some sculpturing, and with two semicircular marks anteriorly, and bearing three pairs of simple setae (Text-fig. 60). Genital shield convex posteriorly and bearing a single pair of setae. Ventri-anal shield slightly wider than long (162-190 [i long X 177- 228 fi wide), reticulated, and bearing nine simple setae. Between the genital and ventri-anal shields lie four small sclerotized plates. Stigma situated between coxae III and IV ; peritreme extending posterior to coxa IV. Metapodal plates narrow. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 61. Leg I (578-782 IJL long) with the tarsus (144-184 /*) longer than the tibia (101- 126 fi) ; claws small, pulvillus short. Setae on tarsus and tibia fine, those on remaining segments stouter. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes (Text-fig. 62). MALE. Unknown. 56 THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) DISTRIBUTION. Oudemans (1903) did not state the locality for his type female, but Buitendijk (1945) in his catalogue of the Oudemans Collection gives the locality as Borkum Island, Germany. Willmann (1952) records the species from the North Sea island of Wangerooge, and says it is found as far up as Lapland. We have examined specimens from the following localities : Kirkstone Pass, River Brathey and High Pike, Ambleside, Westmorland ; Rambulls Moor, Ilkley, Yorkshire ; FIGS. 59-62. Sejus necorniger (Oudemans), female. Fig. 59, dorsum. Fig. 60, venter. Fig. 61, chelicera. Fig. 62, tarsus II. Hathersage, Derbyshire ; Sea Houses, Northumberland ; Burton Marsh, Cheshire ; Llyn Idwal, Caernarvonshire ; South Wales ; Washford, Somerset ; Kiel, Germany ; Ohrid, Montenegro ; and Grabouw, Transvaal. Sejus borealis (Berlese) comb. nov. Ameroseius borealis Berlese, A., 1904, Redia, 1 : 259. Episeius montanus Willmann, C., 1949, Veroff. Mus. Nat. Bremen, No. lA : 120. syn. nov. Episeius montanus Willmann, C., 1952, Veroff. Inst. Meeresf. Bremerhaven, 1 : 148. Episeius montanus Willmann, C., 1952, SB. ost. Akad. Wiss., Abt. i, 162 : 462. FEMALE. Dorsal shield (570-581 JJL long x 361-371 fi wide) covered by a reticu- lated pattern (Text-fig. 63). " Anterior dorsal shield " bears twenty-one pairs of simple setae; verticals anteriorly projected. "Posterior dorsal shield" bears THE PLATYSEIINAE (MESOSTI GM AT A : ACEOSEJIDAE) 57 fifteen pairs of simple setae ; J5 are at the most half the length of J4. The majority of the dorsal setae arise from small tubercles. The distribution and relative length of the setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed and flanked at its base by a pair of narrow pre- endopodal shields. Sternal shield with a narrow longitudinal reticulated area, and bearing three pairs of simple setae (Text-fig. 64). Genital shield convex posteriorly and bearing a single pair of setae. Ventri-anal shield broader than long (139-164 [i long X 202-205 fi wide), reticulated and bearing eleven simple setae. Between the genital and ventri-anal shield lies a row of four small plates, and, posterior to these, FIGS. 63-66. Sejus borealis (Berlese), female. Fig. 63, dorsum. Fig. 64, venter. Fig. 65, chelicera. Fig. 66, tarsus II. two smaller plates. Stigma situated between coxae III and IV with the posterior prolongation of the peritreme extending to about the middle of coxa IV. Metapodal plates circular. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 65. Leg I (576-580 fi long) with the tarsus (137-139 /*) longer than the tibia (108- 114/4). Setae on tarsus and tibia I fine ; ambulacrum and claws small ; remaining setae stouter and arising from small protuberances. Tarsi II-IV with a pair of ZOOL. 6, NO. 2. 5 58 THE PLATYSEIINAE (MESOSTI GM AT A : ACEOSEJIDAE) lanceolate setae, and ambulacra with three acuminate lobes (Text-fig. 66). Setae of legs II-IV arising mainly from small protuberances. MALE. Unknown. DISTRIBUTION. Berlese's (1904) description of the female of Ameroseius borealis is based on material collected by Thor in Norway. His type specimen has been examined by us. Willmann (1949) described Episeius montanus from Poland ; in 1952 he recorded the species from the North Sea island of Wangerooge, and in 1953 he recorded it from several localities in the eastern Alps. The writers have examined five females from Soil Insecticide Experiment, Bellahouston Park, Glasgow, October, 1951, collected by J. G. Sheals ; one female from ditch-side debris near Markfield, Leicestershire, 19.^.1958, collected by P. N. Lawrence ; and one female from wet moss at West Carter Basin, Labrador, I7.viii.i958, also collected by P. N. Lawrence. Sejus serratus (Halbert) comb. nov. Paraseius serratus Halbert, J. N., 1915, Proc. R. Irish Acad,, 39ii : 78. Lasioseius (L.) serratus, Schweizer, J., 1922, Ver. naturf. Ges. Basel, 33 : 43. Episeius serratus, Schweizer, J., 1949, Res. Rech. sci. Pare Nat. Suisse, N.F. 2 : 63. Episeius serratus, Willmann, C., 1949, Veroff. Mus. Bremen, 1A : 120 ; 1954, I n Spiegel, Land-Tierwelt, 15 Ordnung, Acarina .'351. FEMALE. Dorsal shield (440-570 fi long x 286-351 /i wide) with a pattern of irregular reticulations and depressions (Text-fig. 67). "Anterior dorsal shield" with twenty-one pairs of simple setae ; verticals on small tubercles and directed laterally. "Posterior dorsal shield" with fifteen pairs of simple setae. The distribution of the dorsal setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum with a narrow base and pilose laciniae. Sternal shield with some sculpturing laterally, with a pair of circular marks anteriorly, and bearing three pairs of simple setae (Text-fig. 68). Genital shield convex posteriorly and bearing a single pair of setae. Ventri-anal shield slightly wider than long (152-170 /* long X 165-200 /* wide), reticulated anteriorly and bearing nine simple setae. Between the genital and ventri-anal shields lie a row of small plates and behind these a further pair. Stigma situated between coxae III and IV ; peritreme extending posterior to coxa IV. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 69. Leg I (528-718 /i long) with the tarsus (121-149 /) shorter than the tibia (139- 164 fi). Claws on leg I small ; pulvillus short. Setae on tarsus and tibia fine ; those on remaining segments stouter. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes. MALE. This sex is described and figured by Schweizer (1922 & 1949). DISTRIBUTION. Halbert (1915), in the Clare Island Survey, described this species from specimens " Found commonly in sphagnum, gathered on the slopes of Croagh- THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 59 patrick at an elevation of about 600 ft., during the month of October ". Schweizer (1922 & 1949) records both sexes from the Swiss Alps, and Willmann (1954) records the female from Austria. The Museum Collections contain the following specimens : one female in Sphagnum from marsh, Raise Beck, Grasmere, Westmorland, 900 ft., 29. vi. 1951, collected by J. T. Salmon ; three females in mosses and liverworts on rocks by south-east bank of Rydal Water, Westmorland, 29. vi. 1956, collected by FIGS. 67-69. Sejus serratus (Halbert), female. Fig. 67, dorsum. Fig. 68, venter. Fig. 69, chelicera. P. N. Lawrence ; one female in Sphagnum at Blelham Tarn, Lancashire, 22 .iii. 1955, collected by R. J. Elliott ; one female in Sphagnum at Box Hill, Surrey, 30. vi. 1951, collected by E. Duffey ; and two females in moss at West Carter Basin, Labrador, 7.viii.i958, collected by P. N. Lawrence. Sejus curtipes (Halbert) comb. nov. Lasioseius (Episeius) glaber var. curtipes Halbert, J. N., 1923., /. Linn. Soc. Lond. (Zool.), 35 : 37- Episeius ovaspini Schweizer, J., 1949, Res. Rech. sci. Pare Nat. Suisse, N.F. 2 : 69, syn. nov. FEMALE. Dorsal shield (456-529 /* long x 258-320 fi wide) with a reticulated pattern (Text-fig. 70). " Anterior dorsal shield " with fifteen pairs of simple setae. 6o THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) The distribution of the setae, and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum with pilose laciniae. Sternal shield very faintly sculptured and bearing three pairs of simple setae (Text-fig. 71). Genital shield convex posteriorly and bearing a single pair of setae. Ventri-anal shield wider than long (120-160 /* long X 154-218 11 wide), reticulated in its anterior half, and bearing nine simple setae. Between the genital and ventri-anal shields lies a pair of long narrow platelets and behind these two shorter platelets. Stigma situated between coxae III and IV ; peritreme extending posterior to coxa IV. Metapodal plates small. FIGS. 70-73. Sejus curtipes (Halbert), female. Fig. 70, dorsum. Fig. 71, venter. Fig. 72, chelicera. Fig. 73, tarsus II. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 72. Leg I (443-518 fi long) with the tarsus (113-139 /i) longer than the tibia (68- 88 fi). Claws on leg I small, pulvillus short ; setae on tarsus and tibia fine, those on remaining segments stouter. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes (Text-fig. 73). MALE. This sex is described and figured by Schweizer (1949 : 71). DISTRIBUTION. Halbert's (1923) description of Lasioseius (Episeius) glaber van THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 61 curtipes is based on two females found amongst wet moss on Lambay Island, Co. Dublin, in July. Schweizer's (1949) description of Episeius ovaspini is based on five males and thirty-two females collected in wet mosses in the Swiss National Park. We have examined Halbert's type and a number of Schweizer's type series ; also five females from the summit of Snowdon, Caernarvonshire, August, 1951, collected by E. Duffey ; and eleven females from Jamaica, B.W.I., collected by P. F. Bellinger ; seven in moss on concrete, Coolsbade, Portland, I7.vii.i955, and four in moss, west side of John Cove Mountains, 2,300 ft., 25. v. 1956. Sejus cassiteridum sp. nov. FEMALE. Dorsal shield (435-467 fj, long x 237-258 /* wide) heavily sculptured and with a network of ridges and depressions. Lateral margins irregular (Text-fig. 74). "Anterior dorsal shield" with twenty-one pairs of simple setae; verticals 75 FIGS. 74-78. Sejus cassiteridum sp. nov., female. Fig. 74, dorsum. Fig. 75, venter. Fig. 76, tectum. Fig. 77, chelicera. Fig. 78, tarsus II. close together and projecting anteriorly. "Posterior dorsal shield" with fifteen pairs of simple setae of which J5 are the shortest. The distribution and relative lengths of the dorsal setae and the ornamentation of the dorsal shield are shown in the Text-fig. 62 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) Tritosternum well developed with pilose laciniae. Sternal shield almost entirely without sculpturing, and bearing three pairs of short simple setae (Text-fig. 75). Genital shield slightly convex posteriorly and bearing a single pair of setae. Ventri- anal shield wider than long (115-139 fi long X 152-165 /* wide), reticulated and bearing nine simple setae. Between the genital and ventri-anal shields lie six small sclerotized plates. Stigma situated between coxae III and IV ; peritreme and peritrematal shields extending posterior to coxa IV. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 76) three-pronged. The dentition of the chelicera is shown in Text-fig. 77. Leg I (372-387 fi long) with the tarsus (99-106 fi) almost twice the length of the tibia (58-63 fi). Setae on tarsus and tibia fine, those on other segments stouter ; pulvillus short and tarsal claws small. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes (Text-fig. 78). MALE. Unknown. LOCALITY. England. The holotype female (1959.1.20.92) and twenty-five paratype females (1959 . i . 20 . 93-102) occurring with Platyseius subglaber (Oudemans) in the roots of rushes by Big Pool, St. Agnes, Isles of Scilly, Cornwall, 19. ix. 1957, collected by K. H. Hyatt. The writers have examined a single female (1959.1.20.193) from Sphagnum, Blelham Tarn, Windermere, Lancashire, 22 .iii. 1955, collected by R. J. Elliott, which differs from the St. Agnes specimens by having the sternal shield conspicuously reticulated. The measurements of this specimen all fall within the ranges given above for Sejus cassiteridum (viz. : dorsal shield 446 x 247 fi, ventri-anal shield 126 x 157 11, leg I 392 /*, tarsus I 101 /*, tibia I 63 ju,). Sejus dromadis sp. nov. FEMALE. Dorsal shield (393 /* long x 230 p wide) oval in outline, heavily reticulated, and steeply humped dorso-medially (Text-fig. 79). " Anterior dorsal shield " with twenty-three pairs of setae ; " posterior dorsal shield " with fifteen pairs of setae (Text-fig. 80). The verticals are stout and spiculate, and the re- mainder of the setae are stout and pilose. The distribution and relative lengths of the dorsal setae, and the form of the dorsal shield are shown in the Text-figs. Tritosternum less strongly developed than in the majority of species of Sejus. Laciniae pilose. Sternal shield weakly sclerotized with three pairs of simple setae. Genital shield broadly flask-shaped with one pair of setae (Text-fig. 81). Ventri- anal shield small (83 fi long x 88 ju, wide), weakly sclerotized, and bearing seven simple setae. Two small sclerotized plates lie on the interscutal membrane between the genital and ventri-anal shields. Stigma situated between coxae III and IV, with the peritreme not extending posterior to the stigma. Peritrematal shield extending a little posterior to the stigma. Venter of gnathosoma with rostral and internal palptrochanter setae long and whip-like (Text-fig. 82). All setae on pedipalp simple. Tectum three-pronged and THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 82 FIGS. 79-85. Sejus dromadis sp. nov., female. Fig. 79, lateral view of dorsum. Fig. 80, dorsal shield. Fig. 81, venter. Fig. 82, venter of gnathosoma. Fig. 83, tectum. Fig. 84, chelicera. Fig. 85, tarsus II. 6 4 THE PLATYSEIINAE (MESOSTI GM ATA : ACEOSEJIDAE) typical of the genus (Text-fig. 83). The dentition of the chelicera is shown in Text-fig. 84. Leg I (about 300 /* long) with the tarsus (70 /*) longer than the tibia (56 fi). Setae on tarsus fine ; those on remaining segments stouter, and in some cases spiculate and arising from small protuberances. Tarsi II-IV with a pair of lanceolate setae. Ambulacrum of tarsus I short and claws small. Pulvilli of tarsi II-IV produced into three acuminate lobes (Text-fig. 85). MALE. Unknown. LOCALITY. England. A single female (1959.1.20.103) in cow dung at Canter- bury, Kent, collected by the late Dr. E. Warren. Sejus areolatus sp. nov. FEMALE. Dorsal shield (361 fi long X 216 ju, wide) completely covered by a fine reticulated pattern; margin irregular (Text-fig. 86). "Anterior dorsal shield" FIGS. 86-90. Sejus areolatus sp. nov., female. Fig. 86, dorsum. Fig. 87, venter. Fig. tectum. Fig. 89, chelicera. Fig. 90, tarsus II. with twenty-one pairs of simple setae ; verticals with their bases touching, and considerably shorter than post-verticals. "Posterior dorsal shield" with fifteen pairs of simple setae. The distribution of the setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed with pilose laciniae. Sternal shield almost plain, THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 65 with three pairs of simple setae (Text-fig. 87). Genital shield bearing a single pair of setae. Ventri-anal shield wider than long (106 /* long x 132 /* wide), reticulated, with five small oval areas forming a crescent behind the paranals, and bearing nine simple setae. Between the genital and ventri-anal shields lies a row of four sclero- tized platelets, and behind these two smaller ones. Stigma situated between coxae III and IV ; peritreme extending posterior to coxa IV. Metapodal plates small and narrow. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged (Text-fig. 88), the centre prong being in advance of the lateral ones. The dentition of the chelicera is shown in Text-fig. 89. Leg I (c. 330 ju, long) with the tarsus (88 /*) longer than the tibia (50 /*). Setae on tarsus and tibia fine, those on remaining segments stouter ; claws small, on short pulvillus. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes (Text-fig. 90). MALE. Unknown. LOCALITY. Uganda. A single female, the holotype (1959.1.20.104), from rushes and grassland bordering hot springs, sixteen miles east-north-east of Bundi- bugyo, Ruwenzori, 29.viii.i952, collected by G. Owen Evans. Sejus kennedyi sp. nov. FEMALE. Dorsal shield (456-467 jn long x 268-279 /i wide) covered by a network of small depressions and ridges (Text-fig. 91). " Anterior dorsal shield " with twenty-one pairs of simple setae ; verticals separated by the width of their bases and projecting anteriorly. "Posterior dorsal shield" with fifteen pairs of simple setae of which J5 are short. The distribution and relative lengths of the dorsal setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum with a pair of pilose laciniae. Sternal shield plain and bearing three pairs of simple setae (Text-fig. 92). Genital shield lightly reticulated, convex posteriorly, and bearing one pair of simple setae. Ventri-anal shield broader than long (139-144 ju, long x 208-213 fi wide), reticulated, and bearing nine simple setae. Between the genital and ventri-anal shields lie two narrow sclerotized platelets. Stigma situated between coxae III and IV ; peritreme crenate along its internal margin, and with no post-stigmal prolongation. Peritrematal shield tapering and extending posterior to coxa IV. Metapodal shields obliquely situated. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. Chelicerae typical. Leg I (354 /* long) with the tarsus (88 /*) longer than the tibia (63 /*). Setae on tarsus I fine, ambulacrum and claws small ; setae on remaining segments stouter and arising from small protuberances. Tarsi II-IV with a pair of lanceolate setae and ambulacra with three acuminate lobes. MALE. Unknown. 66 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) LOCALITY. Uganda. The holotype female (1959.1.20.105) and three paratype females (1959.1.20.106-108) from litter under hardwood stand, Bimdibugyo, Ruwenzori, 3,400 ft., 2.ix.i952, collected by G. Owen Evans. This species is named after Professor W. Q. Kennedy, University of Leeds, leader of the British Ruwenzori Expedition, 1952. 91 92 FIGS. 91-92. Sejus kennedyi sp. nov., female. Fig. 91, dorsum. Fig. 92, venter. Sejus phalangioides sp. nov. FEMALE. Dorsal shield (398-410 fi long x 250-253 // wide) attenuated in the posterior half, and covered by a fine reticulated pattern (Text-fig. 93). " Anterior dorsal shield " with twenty-one pairs of simple setae, verticals projecting anteriorly ; "posterior dorsal shield" with fifteen pairs of simple setae, of which J5 are the shortest. The distribution and relative lengths of the dorsal setae are shown in the Text-fig. Tritosternum well developed and flanked at its base by a pair of narrow pre- endopodal shields. Sternal shield with a reticulated area anteriorly, and bearing three pairs of simple setae (Text-fig. 94). Genital shield broad, truncated posteriorly, THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 67 distinctly reticulated, and bearing a single pair of setae. Ventri-anal shield slightly broader than long (101 fi long X 116 fi wide), attenuated posteriorly, reticulated, and bearing nine simple setae. Between the genital and ventri-anal shields lies a narrow, undulated, sclerotized strip of chitin, and two platelets. Stigma situated between coxae III and IV, peritreme scarcely extending posterior to the stigma. FIGS. 93-99. Sejus phalangioides sp. nov., female. Fig. 93, dorsum. Fig. 94, venter. Fig. 95, tectum. Fig. 96, chelicera. Fig. 97, leg IV. Fig. 98, tarsus II. Fig. 99, entire mite, showing relative lengths of legs and idiosoma. Peritrematal shield fused with well developed podal plates, which extend posterior to coxa IV. Metapodal plates small, situated close to podal plates. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- 68 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) like. All setae on pedipalp simple. Tectum (Text-fig. 95) three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 96. Leg I (536 [i long) has the tarsus (139 fi) longer than the tibia (100-106 /*). Setae on tarsus I very fine ; those on remaining segments stouter. Ambulacrum of tarsus I short, claws small. Leg IV (954 fji long) more than twice the length of the idiosoma, with the tarsus about 400 ju, long (Text-fig. 97). Tarsi II-III with a pair of lanceolate setae, and pulvilli produced into three acuminate lobes (Text-fig. 98). Tarsus IV without lanceolate setae, and pretarsus long (55 /*). The relative lengths of the legs and the idiosoma are shown in Text-fig. 99. MALE. Unknown. LOCALITY. Uganda. The holotype female (1959.1.20.109) and one paratype female (1959.1.20.110) in grassland in forest clearing near stream, nine miles north-east of Bundibugyo, Ruwenzori, 2,850 ft., 24.viii.i952, collected by G. Owen Evans. Sejus signatus sp. nov. FEMALE. Dorsal shield (581 ju, long x 371 fi wide) weakly sclerotized and covered by a reticulated pattern (Text-fig. 100). " Anterior dorsal shield " with twenty FIGS. 100-102. Sejus signatus sp. nov., female. Fig. 100, dorsum. Fig. 101, venter. Fig. 1 02, chelicera. THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 69 pairs of simple setae ; verticals considerably shorter than post-verticals, and well separated. " Posterior dorsal shield " with fifteen pairs of simple setae. The distribution of the dorsal setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum with pilose laciniae. Sternal shield weakly sclerotized, with an M-shaped mark anteriorly and bearing three pairs of simple setae (Text-fig. 101). Genital shield weakly sclerotized and bearing one pair of setae. Ventri-anal shield wider than long (152 /* long x 197 /* wide), weakly sclerotized and bearing nine simple setae. Between the genital and ventri-anal shields lie a narrow sclerotized strip and two platelets. Stigma situated between coxae III and IV ; peritreme extending posterior to coxa IV. Metapodal plates very small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 102. Leg I (573 fi long) with the tarsus (141 fi) longer than the tibia (99 /*). Claws on leg I small, inconspicuous, pulvillus short. Setae on tarsus and tibia fine, those on other segments stouter. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes. MALE. Unknown. LOCALITY. Uganda. A single female, the holotype (1959.1.20.111), from damp decaying vegetation and soil under elephant-grass at Ibanda, Ruwenzori, 26 . vii . 1952, 4,760 ft., collected by G. O. Evans. Sejus spinipes sp. nov. FEMALE. Dorsal shield (392 fi long X 216 /* wide) covered by a light reticulated pattern (Text-fig. 103). " Anterior dorsal shield " bears twenty-one pairs of simple setae ; verticals anteriorly projecting. " Posterior dorsal shield" bears 15 pairs of simple setae ; J5 are as long as J4- The majority of the dorsal setae arise from small tubercles. The distribution and relative lengths of the dorsal setae, and the orna- mentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed with pilose laciniae. Sternal shield with the central area reticulated, and bearing three pairs of short simple setae (Text-fig. 104). Genital shield with a single pair of simple setae. Ventri-anal shield broader than long (119 fi long X 157 /* wide), distinctly reticulated and bearing nine simple setae. Between the genital and ventri-anal shields lies a line of four contiguous sclerotized plates, and, postero-laterally to these, four smaller plates. Stigma situated between coxae III and IV, with the posterior prolongation of the peritreme extending to about the middle of coxa IV. The peritrematal shield extends posterior to coxa IV. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 105) three-pronged. The dentition of the chelicera is typical of the genus. 7 o THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE Leg I ( c. 330 fi long) with the tarsus (76 fi) longer than the tibia (53 /<). Setae on tarsus I fine ; ambulacrum and claws small ; many of the setae on remaining segments stout and arising from conspicuous protuberances. Tarsi II-IV with a pair of lanceolate setae, and ambulacra with three acuminate lobes. Setae of legs II-IV mainly stout and arising from conspicuous protuberances. MALE. Unknown. LOCALITIES. Uganda and Sudan. The holotype female (1959.1.20.112) from FIGS. 103-105. Sejus spinipes sp. nov., female. Fig. 103, dorsal shield. Fig. 104, venter. Fig. 105, chelicera. rushes and grassland bordering hot springs, sixteen miles east-north-east of Bundi- bugyo, Ruwenzori, Uganda, 29.viii.i952, collected by G. O. Evans; and two paratype females (1959.1.20.113-114) on Papyrus in the Sudd Region, Southern Sudan, collected by I. W. B. Thornton. THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 71 Sejus nepalensis sp. nov. FEMALE. Dorsal shield (456-498 //. long X 289-299 fi wide) completely covered by a fine reticulated pattern (Text-fig. 106). " Anterior dorsal shield " with twenty- one pairs of simple setae ; vertical setae relatively short and directed laterally ; vertex not well developed. " Posterior dorsal shield " with fifteen pairs of simple setae (in the holotype seta Zi is missing from the left side) ; seta J5 is the shortest. All dorsal setae arise from small tubercles. The distribution and relative lengths of the setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed, with pilose laciniae, sternal shield with some 106 FIGS. 106-109. Sejus nepalensis sp. nov., female. Fig. 106, dorsum. Fig. 107, venter. Fig. 108, chelicera. Fig. 109, tarsus II. sculpturing, a pair of circular areas anteriorly, and bearing three pairs of simple setae (Text-fig. 107). Genital shield almost parallel sided and bearing one pair of simple setae. Ventri-anal shield (126 /* long X 124-127 //. wide) almost circular in outline, bearing nine simple setae ; anus more or less central. Between the genital and ventri-anal shields lie about four narrow platelets. Stigma situated between coxae III and IV ; peritreme extending posterior to coxa IV. Metapodal plates very small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 108. 72 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) Leg I (630-769 fi long) with the tarsus (126-157 /*) shorter than the tibia (150- 195 fi}. Setae on tarsus, tibia and genu very fine ; those on remaining segments stouter. Claws very small, pulvillus short. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes (Text-fig. 109). MALE. Unknown. LOCALITY. Nepal. The holotype female (1959.1.20.115) from sandy turf on open grazed hillside facing south at Siklis (28 22' N., 84 6' E.), 7,000 ft., 20- 21. iv. 1954; and one paratype female (1959.1.20.116) from damp mossy and grassy earth under shade of trees and rocks at Bakhri Kharka (28 22-5' N., 84 7-5' E.), 5,500 ft., 24. iv. 1954, collected by K. H. Hyatt. Sejus parbatensis sp. nov. FEMALE. Dorsal shield (402-435 /* long x 237-268 ^ wide) covered by an irregular reticulated pattern (Text-fig, no). " Anterior dorsal shield " with twenty- FIGS. 110-113. Sejus parbatensis sp. nov., female. Fig. no, dorsum. Fig. in, venter. Fig. 112, chelicera. Fig. 113, tarsus II. one pairs of simple setae ; verticals with their bases contiguous. " Posterior dorsal shield " with fifteen pairs of simple setae ; setae J5 are more than half the length of J4. All the setae arise from small tubercles. The distribution of the setae, and the ornamentation of the dorsal shield are shown in the Text-fig. THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 73 Tritosternum well developed and with pilose laciniae. Sternal shield lightly sculptured and bearing three pairs of simple setae (Text-fig, in). Genital shield bearing a single pair of setae. Ventri-anal shield wider than long (114-126 ju, long X 157-170 /* wide), reticulated, and bearing nine simple setae. Between the genital and ventri-anal shields lies a row of four narrow platelets, and, posterior to these, two smaller ones. Stigma situated between coxae III and IV ; peritreme extending posterior to coxa IV. Metapodal plates very small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 112. Leg I (c. 340 /* long) with the tarsus (80-83 /*) longer than the tibia (50-53 ju). Setae on tarsus I very fine ; those on remaining segments stouter ; claws small, on short pulvillus. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes (Text-fig. 113). MALE. Unknown. LOCALITY. Nepal. The holotype female (1959.1.20.117) and one paratype (1959.1.20.118) from litter under a group of deciduous trees forming a canopy on open ground at Gurjakhani (28 36-5' N., 83 13-5' E.) on the southern slope of the Dhaulagiri Himal, 8,500 ft., 24-27^1.1954 ; and one paratype female (1959.1.20. 119) in sandy turf on open, grazed hillside facing south at Siklis (28 22' N., 84 6' E.), 7,000 ft., 2O-2i.iv. 1 954, collected by K. H. Hyatt. Sejus clayi sp. nov. FEMALE. Dorsal shield (661 /* long X 366 /* wide) with lateral incisions anterior to Si, and heavily marked with circular depressions (Text-fig. 114). Vertex of dorsal shield produced anteriorly (Text-fig. 115). "Anterior dorsal shield" with twenty pairs of setae ; verticals absent, para-verticals short and spatulate, remaining setae simple. " Posterior dorsal shield " with fifteen pairs of simple setae. Setae J5 are long. The distribution and relative lengths of the dorsal setae are shown in Text-fig. 114. Tritosternum well developed with pilose laciniae and flanked at its base by a number of fragmented pre-endopodal shields. Sternal shield plain and bearing three pairs of simple setae (Text-fig. 116). Genital shield wedge shaped, genital setae off the shield. Ventri-anal shield slightly wider than long (185 fi long X 190 /* wide), covered with small circular depressions, and bearing only five simple setae. Stigma situated between coxae III and IV, peritreme not extending posterior to the stigma; external margin of peritreme strongly crenate. Peritrematal shield extending posterior to coxa IV. Metapodal shields narrow and obliquely situated. Venter of the gnathosoma with rostral and internal palptrochanter setae long, whip-like. All setae on legs simple. Tectum (Text-fig. 117) differing from that of other members of the genus in that the median prong is strongly produced and terminates in a pair of pilose laciniae. The dentition of the chelicera is shown in Text-fig. 118. ZOOL. 6, NO. 2. 74 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) Leg I (481 /* long) with the tarsus (126 /*) longer than the tibia (101 /i). Setae on tarsus I very fine ; those on remaining segments stouter. Tarsi II-IV with a pair of lanceolate setae and ambulacra with lateral lobes acuminate, median lobe short and rounded (Text-fig. 119). Ambulacrum of tarsus I short with claws very small. MALE. Unknown. 115 117 \ I) 119 118 FIGS. 114-119. Sejus clayi sp. nov., female. Fig. 114, dorsum. Fig. 115, vertex. Fig. 116, venter. Fig. 117, tectum. Fig. 118, chelicera. Fig. 119, tarsus II. LOCALITY. Sikkim. A single female (1959.1.20.120) from leaves and leaf- mould in wood on steep hillside, Chungtang, 5,120 ft., 16.^.1952, collected by Dr. Theresa Clay. Sejus alstoni sp. nov. FEMALE. Dorsal shield (507-550 ju, long X 279-340 /* wide) covered anteriorly by a network of small depressions and ridges, and posteriorly by a reticulated THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 75 pattern (Text-fig. 120). " Anterior dorsal shield " with twenty-one pairs of simple setae ; verticals close together and directed anteriorly. " Posterior dorsal shield " with fifteen pairs of simple setae, of which J5 are the shortest. The distribution and relative lengths of the dorsal setae, and the ornamentation of the dorsal shield are shown in the Text-fig. FIGS. 120-123. Sejus alstoni sp. nov., female. Fig. 120, dorsum. Fig. 122, tectum. Fig. 123, tarsus II. 121 Fig. 121, venter. Tritosternum well developed with pilose laciniae, and flanked at its base by a pair of narrow pre-endopodal shields. Sternal shield weakly sclerotized, without ornamentation, and bearing three pairs of simple setae (Text-fig. 121). Genital shield truncated posteriorly and bearing one pair of setae. Ventri-anal shield broader than long (139-152 IJL long X 180-205 / wide), reticulated, and bearing nine simple setae. Between the genital and ventri-anal shields lies a row of three narrow sclerotized plates. Stigma situated between coxae III and IV ; no posterior prolongation of the peritreme. Peritrematal shield extending posterior to coxa IV. Metapodal shields elliptical. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- 76 THE PLATYSEIINAE (MESOSTIGMAT A : ACEOSEJIDAE) like. All setae on pedipalp simple. Tectum (Text-fig. 122) three-pronged and typical of the genus. Chelicerae typical. Leg I (560-565 fi long) with the tarsus (160 p) one-and-a-half times as long as the tibia (101-104 /*). Setae on tarsus fine ; claws small ; setae on remaining segments stouter. Tarsi II-IV with a pair of lanceolate setae and ambulacra with three acuminate lobes (Text-fig. 123). MALE. Unknown. LOCALITY. Indonesia. The holotype female (1959.1.20.121) and two paratype females (1959.1.20.122-123) in decaying vegetation at Bogor, 1954, collected by the late A. H. G. Alston. Sejus aciculatus sp. nov. FEMALE. Dorsal shield (329-341 /* long x 223-231 p wide) very heavily sclero- tized, entirely covered by a network of ridges and depressions (Text-fig. 124). " Anterior dorsal shield" with nineteen pairs of simple setae, verticals and para- verticals apparently absent. " Posterior dorsal shield " with fifteen pairs of simple setae. The distribution and relative lengths of the dorsal setae, and the charac- teristic ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed and flanked at its base by a pair of strong pre- endopodal shields which abut the sternal shield. Sternal shield characteristically ornate (Text-fig. 125) and bearing three pairs of simple setae. Genital shield approximately in the form of a trapezium, heavily sclerotized and ornate, and bearing a single pair of simple setae. Ventri-anal shield broader than long (88-96 /i long X 172-180 /* wide), concave anteriorly, strongly ornate, and bearing nine simple setae. Between the genital and ventri-anal shields lies a pair of narrow sclerotized platelets. Stigma situated between coxae III and IV and peritreme not extending posterior to the stigma. Peritrematal shield well developed and extending posterior to coxa IV. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 126) three-pronged, median prong broad and triangular, lateral prongs small, inconspicuous. Dentition of chelicera as in Text-fig. 127. Leg I (245-255 fJi long) with the tarsus (88-94 /*) twice the length of the tibia (43-45 fi). Setae on tarsus I very fine, ambulacrum short, claws small. Setae of remaining segments stouter. Tarsi II-IV with a pair of lanceolate setae, and ambulacra with three acuminate lobes (Text-fig. 128). MALE. Dorsal shield (276-283 fi long x 180-185 /* wide) with ornamentation and chaetotaxy similar to the female. Tritosternum of the same form as that of the female. The chaetotaxy and sclerotization of the venter are shown in Text-fig. 129. The gnathosoma and tectum are similar to those of the female. The spermatophoral process is about the same length as the movable digit of the chelicera (Text-fig. 130). THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 77 FIGS. 124-130. Sejus aciculatus sp. nov. Fig., 124 dorsal shield of female. Fig. 125, venter of female. Fig. 126, tectum of female. Fig. 127, chelicera of female. Fig. 128, tarsus II of female. Fig. 129, venter of male. Fig. 130, chelicera of male. 78 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) Leg I (281 11 long) with the tarsus (81 /*) twice the length of the tibia (38 /*). The chaetotaxy and ambulacra of the legs are as in the female. LOCALITY. Jamaica, B.W.I. The holotype female (1959.1.20.124), allotype male (1959.1.20.125), seven female and three male paratypes (1959.1.20.126-133) from damp leaf litter at St. Ann, Mt. Diablo, 1,500 ft. and 2,200 ft., 3^.1956, collected by P. F. Bellinger. A male and female paratype have been returned to the collector. Sejus antillanus sp. nov. FEMALE. Dorsal shield (333-443 /* long x 195-278 /* wide) slightly attenuated in its posterior half, and entirely covered by a reticulated pattern (Text-fig. 131). " Anterior dorsal shield " with twenty-one pairs of simple setae, verticals almost contiguous and directed anteriorly. " Posterior dorsal shield" with fifteen pairs of simple setae ; J5 are the shortest. The distribution and relative lengths of the setae, and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed with pilose laciniae. Sternal shield with a reticulated area anteriorly and bearing three pairs of simple setae (Text-fig. 132). Genital shield truncated posteriorly, reticulated, and bearing a single pair of setae. Ventri- anal shield broader than long (76-101 ju, long x 101-114 /* wide), reticulated, with nine simple setae of which one pair is long. Between the genital and ventri-anal shields lies a row of four small narrow sclerotized plates, and behind these a pair of smaller plates. Stigma situated between coxae III and IV ; no post-stigmal prolongation of the peritreme. Peritrematal shield extending posterior to coxae IV. Metapodal shields small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 133) three-pronged. The dentition of the chelicera is shown in Text-fig. 134. Leg I (384-521 /* long) with the tarsus (86-139 /*) sn ghtly longer than the tibia (78-114 fi). Setae on tarsus and tibia fine, those on remaining segments stouter ; claws on leg I small. Tarsi II-IV with a pair of lanceolate setae and ambulacra with acuminate lobes (Text-fig. 135). Leg IV (532-797 /*) considerably longer than the idiosoma, with the tarsus 203-316 /* long. MALE. Dorsal shield (236-303 ji long x 147-203 /* wide) having similar chaeto- taxy and ornamentation to the female. The chaetotaxy and sclerotization of the venter are shown in Text-fig. 136. The gnathosoma and tectum are similar to those of the female. The spermatophoral process is about one-and-a-half times the length of the movable digit (Text-fig. 137) . Leg I (238-432 pi long) with the tarsus (76-116 fi) longer than the tibia (63-88 /*). Leg IV (448-658 JLI long) with the tarsus 170-253 ju,. The chaetotaxy and ambulacra of the legs are as in the female. LOCALITY. Jamaica, B.W.I. The holotype female (1959.1.20.134) and four paratype females (1959 . i . 20 . 135-138) from damp leaf litter, Mt. Diablo, St. Ann, 2,200 ft., 7.vi.i956 ; the allotype male (1959.1.20.139) and five paratypes THE PLATYSEIINAE (MESOSTIGMATA : ACEOSEJIDAE) 79 137 FIGS. 131-137. Sejus antillanus sp. nov. Fig. 131, dorsum of female. Fig. 132, venter of female. Fig. 133, tectum of female. Fig. 134, chelicera of female. Fig. 135, tarsus II of female. Fig. 136, venter of male. Fig. 137, chelicera of male. 8o THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 2?$) (1959.1.20.140-144) from damp leaf litter in wood, Dolphin Head, Hanover, 1,780 ft., 13. iv. 1956 ; three paratypes (i^, 2$$) in moss, St. Thomas, John Cove Mountains, 2,300 ft., 25 . v . 1956 ; and ten paratypes (ig, 9$$) (1959 . i . 20 . 145-154) from leaf litter, Portland Gap, 8.iii.i956. All were collected by P. F. Bellinger. A male and two female paratypes have been returned to the collector. FIGS. 138-142. Sejus bellingeri sp. nov. Fig. 138, dorsum of female. Fig. 139, tectum of female. Fig. 140, tarsus I of female. Fig. 141, venter of male. Fig. 142, chelicera of male. THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 81 Sejus bellingeri sp. nov. FEMALE. Dorsal shield (467-507 fi long x 299-310 /i wide) slightly attenuated in its posterior half, and covered by a reticulated pattern (Text-fig. 138). " Anterior dorsal shield ' ' with twenty-one pairs of simple setae ; verticals closely situated and directed anteriorly. " Posterior dorsal shield " with fifteen pairs of simple setae of which J5 are the shortest. The distribution and relative lengths of the setae and the ornamentation of the dorsal shield are shown in the Text-fig. The chaetotaxy and sclerotization of the venter are essentially the same as in Sejus nodosus (p. 85). The ventri-anal shield measures 119-139 /* long X 132-156 fju wide. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 139) three-pronged, and chelicerae typical of the genus. Leg I (c. 589 fi long) with the tarsus (c. 157 /*) longer than the tibia (c. 126 /*). Tarsus I with a strong erect seta dorsally (Text-fig. 140), remaining setae fine ; tarsal claws small but conspicuous. Tarsi II-III with a pair of lanceolate setae (tarsus IV has only one such seta), ambulacra with three acuminate lobes. Leg IV (c. 913 /*) longer than the idiosoma. Tarsus IV (303-341 /JL) markedly elongate and three times the length of the tibia. MALE. Dorsal shield (347 ju, long x 228 JJL wide) not attenuated in its posterior half, lightly reticulated. The chaetotaxy of the dorsal shield is the same as that of the female. The chaetotaxy and ornamentation of the venter are shown in Text-fig. 141. The gnathosoma and tectum are similar to those of the female. Spermatophoral process about twice the length of the movable digit of the chelicera (Text-fig. 142). Leg I (481 IJL long) with the tarsus (126 /*) longer than the tibia (99 fi). Tarsus I with a strong erect seta dorsally as in the female. Leg IV (675 /* long) longer than the idiosoma, and with the tarsus (265 /*) three times the length of the tibia (88 /*). LOCALITY. Jamaica, B.W.I. The holotype female (1959.1.20.155), allotype male (1959.1.20.156) and one paratype female from pine and hardwood litter, St. Thomas, Portland Gap, 5,500 ft., 8.iii.i956, collected by P. F. Bellinger. The paratype has been returned to the collector. Sejus hulli sp. nov. FEMALE. Dorsal shield (359 /* long x 195 p wide) completely covered by a conspicuous reticulated pattern (Text-fig. 143). " Anterior dorsal shield " with twenty-one pairs of simple setae, verticals on a prominent protuberance and directed anteriorly. "Posterior dorsal shield" with fifteen pairs of simple setae, J5 are short. All setae arise from small protuberances. The distribution and relative lengths of the dorsal setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed with pilose laciniae. Sternal shield with a very faint 82 THE PLATYSEIINAE (MESOSTI GM AT A : ACEOSEJIDAE) reticulated area medially, and bearing three pairs of simple setae (Text-fig. 144). Genital shield bearing a single pair of setae. Ventri-anal shield a little broader than long (94 /* long X 114 11 wide), reticulated and bearing nine simple setae. Between the genital and ventri-anal shields lie about six small sclerotized plates. Stigma situated between coxae III and IV ; no distinct post-stigmal prolongation of peri- treme ; peritrematal shield extending posterior to coxa IV. Metapodal plates small. Venter of gnathosoma with rostral and internal seta on palptrochanter long, FIGS. 143-147. Sejus hulli sp. nov., female. Fig. 143, dorsum. Fig. 144, venter. Fig. 145, tectum. Fig. 146, chelicera. Fig. 147 tarsus II. whip-like. All setae on pedipalp simple. Tectum (Text-fig. 145) three-pronged. The dentition of the chelicera is shown in Text-fig. 146. Leg I (360 IJL) with the tarsus (101 /i) nearly twice the length of the tibia (56 /*). Setae on tarsus and tibia fine, those on remaining segments stouter. Claws on leg I minute, tarsus swollen in its distal third. Tarsi II-IV with a pair of lanceolate setae, and ambulacra with acuminate lobes (Text-fig. 147). MALE. Unknown. LOCALITY. Jamaica, B.W.I. A single female (1959.1.20.157) collected in Lycopodium at Fairy Glade, St. Andrew, 6.xii.i956, by P. F. Bellinger. THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 83 Sejus jamaicensis sp. nov. FEMALE. Dorsal shield (477 fi long x 310 jLt wide) concave posteriorly and covered with a light reticulated pattern (Text-fig. 148). " Anterior dorsal shield " with twenty-one pairs of simple setae ; verticals well separated, short, and arising from weak bases. " Posterior dorsal shield " with fifteen pairs of simple setae of which J5 are the shortest. The distribution of the dorsal setae and the ornamenta- tion of the dorsal shield are shown in the Text-fig. 148 FIGS. 148-152. Sejus jamaicensis sp. nov., female. Fig. 148, dorsum. Fig. 149, venter. Fig. 150 tectum. Fig. 151, chelicera. Fig. 152, tarsus II. Tritosternum well developed with pilose laciniae. Sternal shield with a little sculpturing and two circular areas anteriorly (Text-fig. 149), and bearing three pairs of simple setae. Genital shield with one pair of simple setae. Ventri-anal shield wider than long (114-119 p, long x 139-144 /* wide), bearing nine simple setae, and only lightly sculptured. Between the genital and ventri-anal shields lie a row of four narrow platelets and, posterior to these, two smaller ones. Stigma situated between coxae III and IV ; peritreme extending posterior to coxa IV. Metapodal plates very small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 150) three-pronged. The dentition of the chelicera is shown in Text-fig. 151. Leg I (924 fi long) with the tarsus (215 fi) only slightly shorter than the tibia (228 fi). Setae on tarsus, tibia and genu very fine ; those on remaining segments 84 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) stouter. Claws minute, sessile. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes (Text-fig. 152). MALE. Unknown. LOCALITY. Jamaica, B.W.I. The holotype female (1959.1.20.158) and one paratype female from wet leaves in spray zone, Cape Crow Falls, St. Andrew, 31 . iii . 1956, collected by P. F. Bellinger. The paratype has been returned to the collector. Sejus neborealis sp. nov. FEMALE. Dorsal shield (570 fi long X 330-340 p wide) entirely covered by a strong reticulated pattern, and with a sclerotized tubercle in the region of setae 154 FIGS. 153-157. Sejus neborealis sp. nov., female. Fig. 153, dorsum. Fig. 154, venter. Fig. 155, tectum. Fig. 156, chelicera. Fig. 157, tarsus II. J3-J4 (Text-fig. 153). "Anterior dorsal shield" with twenty-one pairs of simple setae, vertical setae contiguous and directed anteriorly. "Posterior dorsal shield " with fifteen pairs of simple setae, J4 situated on the margin of the sclerotized tubercle. The distribution and relative lengths of the dorsal setae, and the ornamentation of the dorsal shield are shown in the Text-fig. THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 85 Tritosternum well developed with pilose laciniae. Sternal shield with a small median reticulated area anteriorly, and bearing three pairs of short simple setae (Text-fig. 154). Genital shield slightly convex posteriorly and bearing one pair of simple setae. Ventri-anal shield broader than long (172-177 p long x 240-253 /* wide), wholly reticulated and bearing nine simple setae. Between the genital and ventri-anal shields lie four sclerotized platelets. Stigma situated between coxae III and IV with the posterior prolongation of the peritreme extending in line with the middle of coxa IV. Peritrematal shield well developed, extending posterior to coxa IV, and crenate externally. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 155) three-pronged. The dentition of the chelicera is shown in Text-fig. 156. Leg I (734-774 }i long) with the tarsus (228-243 /*) approximately twice the length of the tibia (114-126 /*). Some setae on tarsus I relatively long and standing at right angles to the segment ; ambulacrum short, claws small (and inconspicuous) ; setae of remaining segments stouter. Tarsi II-IV with a pair of lanceolate setae and ambulacrum with three acuminate lobes (Text-fig. 157). MALE. Unknown. LOCALITY. Jamaica, B.W.I. The holotype female (1959.1.20.158) and three paratype females (1959.1.20.159-160) collected in moss on concrete, Coolsbade, Portland, 17 . vii . 1956, by P. F. Bellinger. One paratype has been returned to the collector. Sejus nodosus sp. nov. FEMALE. Dorsal shield (518-529 /* long x 310 /* wide) slightly attenuated in its posterior half, and covered by a reticulated pattern (Text-fig. 158). There is a pronounced sclerotized tubercle in the region of setae J3-J4- " Anterior dorsal shield " with twenty-one pairs of simple setae ; vertical setae closely situated and anteriorly directed. "Posterior dorsal shield" with twenty-one pairs of simple setae, of which J5 are the shortest. The distribution and relative lengths of the setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed and with pilose laciniae. Sternal shield plain and bearing three pairs of simple setae (Text-fig. 159). Genital shield slightly convex posteriorly, reticulated, and bearing a single pair of setae. Ventri-anal shield wider than long (114-116 fi long X 134-144 /* wide), lightly sculptured and bearing nine simple setae. Between the genital and ventri-anal shields lies a row of two to four narrow sclerotized platelets. Stigma situated between coxae III and IV ; peritreme not extending posterior to the stigma. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 160) three-pronged, and chelicerae typical of the genus. Leg I (c. 620 fi long) with the tarsus (165 /*) longer than the tibia (126 /*). Tarsus I with a strong erect spine dorsally, remaining setae fine ; tarsal claws small but 86 THE PLATYSEIINAE (MESOSTI GM AT A : ACEOSEJIDAE) conspicuous. Tarsi II-III with a pair of acuminate lobes (Text-fig. 161.) Leg IV is about 913 fi long, with the tarsus 392 /* long, markedly elongate, and three times as long as the tibia. MALE. Unknown. 158 FIGS. 158-161. Sejus nodosus sp. nov., female. Fig. 158, dorsum. Fig. 159, venter. Fig. 160, tectum. Fig. 161, tarsus II. LOCALITY. Jamaica, B.W.I. The holotype female (1959.1.20.161) and one paratype from moss on concrete, Coolsbade, Portland, I7.vii.i955, collected by P. F. Bellinger. The paratype has been returned to the collector. Sejus browningi sp. nov. FEMALE. Dorsal shield (330-354 /* long x 190-210 /i wide) very heavily reticu- lated (Text-fig. 162). "Anterior dorsal shield" with twenty-one pairs of setae; " posterior dorsal shield" with fifteen pairs of setae. Dorsal setae J5 are short and simple, but the remainder are lanceolate (Text-fig. 163). The highest part of the dorsal shield is in the region of setae Ji-j3- The vertex is produced anteriorly. The distribution and relative lengths of the dorsal setae are shown in Text-fig. 162. THE PLATYSEIINAE (MESOSTIGMAT A : ACEOSEJIDAE) 87 Tritosternum with a pair of pilose laciniae. Sternal shield with a narrow longi- tudinal reticulated area anteriorly (Text-fig. 164) and bearing three pairs of simple setae. Genital shield broad, truncated posteriorly, lightly striated and bearing a single pair of simple setae. Ventri-anal shield wider than long (99-101 /* long X 121-139 fi wide), lightly reticulated anteriorly, and bearing nine simple setae. A row of five narrow sclerotized plates lies on the membrane between the genital and ventri-anal shields. Stigma situated between coxae III and IV, with the peritreme 164 FIGS. 162-167. Sejus browningi sp. nov., female. Fig. 162, dorsal shield. Fig. 163, dorsal seta. Fig. 164, venter. Fig. 165, tectum. Fig. 166, chelicera. Fig. 167, tarsus II. extending only a short distance posterior to the stigma. Peritrematal shield extending posterior to coxa IV. Metapodal shields triangular and situated close to the peritrematal shield. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 165) three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 166. Leg I (320-340 fi long) with the tarsus (88 fi) longer than the tibia (58 p). Setae on tarsus I very fine ; those on remaining segments somewhat stouter. Tarsus I is swollen in its distal third ; without ambulacrum. Tarsi II-IV with a pair of lanceolate setae, and ambulacra with lateral lobes acuminate ; median lobe strongly produced and rounded apically (Text-fig. 167). 88 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) MALE. Unknown. LOCALITY. Sikkim and Argentina. The holotype female (1959.1.20.162) and two paratype females (1959.1.20.163-164) from leaves and leaf -mould in a wood on steep hillside, Chungtang, Sikkim, 5,120 ft., i6.ii.i952, collected by Dr. Theresa Clay ; and another paratype female (1959.1.20.165) from rotting vegetable matter, Tucuman City, Argentina, 500 m., January, 1953, collected by Dr. P. Wygodzynsky. Sejus ornatus sp. nov. FEMALE. Dorsal shield (395-400 fi long x 245-253 fi wide) with lateral incisions between setae 82 and 83, and covered by a network of small tubercles (Text-fig. 1 68). Highest part of dorsal shield in the region of setae Ji-j3- " Anterior dorsal shield " with twenty- two pairs of simple setae ; " posterior dorsal shield " with fifteen pairs of simple setae. Setae J5 are long. Vertex of dorsal shield produced ante- 169 FIGS. 168-173. Sejus ornatus sp. nov., female. Fig. 168, dorsum. Fig. 169, venter. Fig. 170, vertex. Fig. 171, tectum. Fig. 172, chelicera. Fig. 173, tarsus II. THE PLATYSEIINAE ' (MESOSTIGMATA : ACEOSEJIDAE) 89 riorly. The distribution and relative lengths of the dorsal setae and the ornamenta- tion of the dorsal shield are shown in the Text-fig. Tritosternum well developed, with pilose laciniae. Sternal shield with a circular impression antero-medially and bearing three pairs of simple setae (Text-fig. 169). Genital shield broad, truncated posteriorly, and bearing a single pair of setae. Ventri-anal shield wider than long (118-139 fi long x 164-177 fi wide), ornamented with small tubercles and punctations and bearing nine simple setae. Stigma situated between coxae III and IV ; peritremes not joined anteriorly (Text-fig. 170), and not extending posterior to the stigmata. Outer margin of peritreme crenate ; peritrematal shield extending to the posterior level of coxa IV. Metapodal shields narrow and transversely situated. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 171) three-pronged, typical of the genus. The dentition of the chelicera is shown in Text-fig. 172. Leg I (360-366 fji long) with the tarsus (103-113 /*) longer than the tibia (58-63 /*). Setae on tarsus I very fine ; those on remaining segments stouter. Tarsi II-IV with a pair of lanceolate setae, and ambulacra with lateral lobes acuminate, median lobe rudimentary (Text-fig. 173). Tarsus I slightly swollen at its distal half, pulvillus and claws small. MALE. Unknown. LOCALITY. Argentina. The holotype female (1959.1.20.166) and three para- types (1959.1.20.167-169) from horse dung and decomposing vegetable matter in forest, Quebrada de los Sosa, Tafi, Tucuman, 1,300 m., 17. v. 1953, collected by Dr. P. Wygodzynsky. Sejus tuberculatus sp. nov. FEMALE. Dorsal shield (477-518 fi long x 310-330 /JL wide) minutely punctured and slightly concave posteriorly (Text-fig. 174). "Anterior dorsal shield" with twenty-one pairs of simple setae. " Posterior dorsal shield " with fifteen pairs of simple setae ; J5 are the shortest. The distribution and relative lengths of the setae, and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum well developed and with pilose laciniae. Sternal shield with faint sculpturing, and bearing three pairs of simple setae (Text-fig. 175). Genital shield flask-shaped, and bearing a single pair of setae. Ventri-anal shield almost circular in outline (130-144 fi long x 144-147 /i wide) and bearing nine simple setae. Between the genital and ventri-anal shields lies a transverse row of about three narrow plates, and posterior to these lie two small plates. Stigma situated between coxae III and IV ; peritreme and peritrematal shields extending posterior to coxa IV. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 176) three-pronged. The dentition of the chelicera is shown in Text-fig. 177. Leg I (794-804 fi long) with the tarsus (162-177 (JL) shorter than the tibia (182- ZOOL. 6, NO. 2. 7 90 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 197 /*). Setae on tarsus, tibia and genu fine ; those on other segments stouter ; tarsal claws minute, inconspicuous. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with three acuminate lobes (Text-fig. 178). MALE. Unknown. I %t -^ i\t I T>, A FIGS. 174-178. Sejus tuberculatus sp. nov., female. Fig. 174, dorsum. Fig. 175, venter. Fig. 176, tectum. Fig. 177, chelicera. Fig. 178, tarsus II. LOCALITY. Argentina. The holotype female (1959 . 1 . 20 . 170) and two paratype females (1959.1.20.171.172) from decaying vegetable matter in forest, Quebrada de los Sosa, Tafi, Tucuman, 13. v. 1953, 1,300 m., collected by Dr. P. Wygodzynsky. The following species also appear to belong to the genus Sejus, but with the exception of Episeius groenlandicus, have not been examined by us : Acarus tendens Schrank, 1803. Fauna Boica, 3 : 209. Oudemans (1929) con- siders this species to be synonymous with Platyseius subglaber (Ouds.). Gamasus scabriculus Nordmann, 1832. Mikr. Beitr. Naturg. wirbell. Thiere : 85. Epicrius glaber Berlese, 1886. A. M.S., 30, No. 9. Italy. Hypoaspis scutulis Banks, 1914. Psyche, 21 : 161. Brazil. Lasioseius borealis var. temperatus Berlese, 1916. Redia, 12 : 34. Palermo. Lasioseius grandis Berlese, 1916. Tom. cit. : 34. Piemonte, Venice. Lasioseius parapodicus Berlese, 1916. Tom. cit. : 35. Java. Lasioseius similis Berlese, 1916. Tom. cit. : 35. Italy. This species may be a THE PLATYSEIINAE (MESOSTIGMAT A : ACEOSEJIDAE) 91 synonym of Sejus serratus (Halbert). Lasioseius mutilus Berlese, 1916. Tom. cit. : 37. Florence. Lasioseius (Cheiroseius) alpestris Berlese, 1916. Tom. cit. : 41. Italy. Episeius major incisus Willmann, 1938. Ann. Hist. not. Mus. Hung., 31 : 168. Hungary. Episeius groenlandicus Haarlev, 1942. Medd. Gronland, 128 : 18. Greenland. Episeius aequaLis Schweizer, 1949. Res. Rech. sci. Pare Nat. Suisse, N.F. 2 : 64. Switzerland. Episeius handschini Schweizer, 1949. Tom. cit. : 71. Switzerland. Episeius salicorniae Willmann, 1949. Veroff. Mus. Nat. Bremen, No. lA : 118. Poland. Episeius longipes Willmann, 1951. SB. ost. Akad. Wiss., Abt. I, 160 : 112. Austria. Platyseius mackerassae Womersley, 1956. /. Linn. Soc. Lond. (Zool.) 42 : 552. Queensland. Genus ZERCONOPSIS Hull Zerconopsis Hull, J. E., 1918, Trans, nat. Hist. Soc. Northumb., 5 : 65. Platyseiine mites with the "posterior dorsal shield" bearing fourteen pairs of setae comprising five pairs in the J and the Z series but only four pairs in the S series (82 being situated on the lateral interscutal membrane). Three to five pairs of dorsal setae stout and paddle-like (Text-figs. 179, 192). Lateral margins of the shield entire or incised anterior to Si. Sternal shield in the female with three pairs of setae ; metasternals situated on platelets. Genital shield wedge shaped, genital setae situated on or off the shield. Ventri-anal shield large and bearing from three to seven pairs of setae in addition to the three setae normally associated with the anus. Male with sterniti-genital and free ventri-anal shield. Peritreme without post-stigmatic process ; peritrematal shield poorly developed posterior to coxa IV. Chaetotaxy of the venter of the gnathosoma and of the pedipalps typical of the subfamily. Chelicerae chelate-dentate, movable digit in the male with a short spermatophoral process ; tectum basically three-pronged. Legs I-IV with a well- developed ambulacrum ; median lobes of pulvilli rounded apically. Type species Gamasus remiger Kramer, 1876 KEY TO SPECIES ADULTS 1. Dorsal shield with distinct lateral incisions anterior to Si (Text-figs. 184 and 197) 2 Lateral margins of the dorsal shield entire ....... 3 2. Genital shield in the female narrow, without setae (Text-fig. 198). Labrador Z. I abradorensis sp. n. (p. 99) Genital shield in the female broad, with a pair of setae (Text-fig. 185). Switzerland Z. muestairi (Schweizer) (p. 94) 3. Dorsal shield with five pairs of paddle-like setae (Text-fig. 192) ; genital shield without setae (Text-fig. 193). Hungary . . Z. decemremiger sp. n. (p. 96) 92 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) Dorsal shield with three pairs of paddle-like setae (Text-figs. 179 and 189) ; genital shield with or without setae .......... 4 4. Genital shield with a pair of setae (Text-fig. 180) ; with one pair of large, subtriangular metapodal shields. Europe ..... Z. remiger (Kramer) (p. 92) Genital shield narrow, without setae (Text-fig. 190) ; with two pairs of metapodal shields. England ....... Z. michaeli sp. n. (p. 95) Zerconopsis remiger (Kramer) Gamasus regimer Kramer, P., 1876, Arch. Naturg., Ameroseius bispinosus Berlese, A., 1910, Redia, 6 : 42 : 93. 6 : 253. FEMALE. Dorsal shield (570-630 /* long X 310-382 /* wide) covered antero- laterally with a distinct reticulated pattern ; posterior and central areas with a lighter network (Text-fig. 179). " Anterior dorsal shield " with twenty- two pairs of setae of which one pair is paddle-like, the remainder simple ; verticals short, each on a tubercle. " Posterior dorsal shield " with fourteen pairs of setae of which two pairs are paddle-like and the remainder simple ; J5 are the shortest. The distribu- tion and relative lengths of the dorsal setae and the ornamentation of the dorsal shield are shown in Text-fig. 179. Tritosternum with a narrow base and pilose laciniae, and flanked by a narrow pair of pre-endopodal shields. Sternal shield with a fine granular pattern and bearing three pairs of simple setae (Text-fig. 180). Genital shield also with granular markings, and bearing one pair of setae. Ventri-anal shield wider than long (220- 223 IJL long x 225-303 [A wide), heavily reticulated and bearing thirteen simple setae. Between the genital and ventri-anal shields lie six platelets. Stigma situated between coxae III and IV with the peritreme not extending posterior to the stigma. Metapodal plates conspicuous. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of the genus. The dentition of the chelicera is shown in Text-fig. 181. Leg I (379-400 fi long) with the tarsus (99-103 /*) longer than the tibia (63-68 /*) ; claws small, pulvillus short. Tarsus I smooth with fine setae ; tibia, genu and femur with majority of setae arising from strong tubercles. Tarsi II-IV with a pair of lanceolate setae ; ambulacra with median lobes of pulvilli rounded apically. MALE. Dorsal shield (530-550 /* long x 299-310 JJL wide) with chaetotaxy and ornamentation similar to the female. Sterniti-genital shield with five pairs of simple setae. Ventri-anal shield (Text-fig. 182) reticulated anteriorly and bearing seventeen simple setae. The gnathosoma, tectum, pedipalps and legs are similar to those of the female. Leg I (c. 420 fi long) with the tarsus (99 fi) and the tibia (68 /*). Sperma- tophoral process about a third as long again as the movable digit of the chelicera (Text-fig. 183). DISTRIBUTION. Kramer (1876) described this species from under fallen leaves without giving a locality, and Berlese (1910) described Ameroseius bispinosus from rotting leaves at Palermo. We have examined specimens from Nadap, Herkules- THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) 93 fiirdo, and Gyertyanliget in Hungary, and British specimens from Goyt Valley, Cheshire, 24. xi. 1940, collected by H. Britten; Rydal Water, Westmorland, 29. xi. 1954, collected by M. E. Bacchus ; Harefield, Middlesex, 22^.1956, collected by A. H. G. Alston; and Avonmouth, Gloucestershire, n.v.i957, collected by P. N. Lawrence. 183 FIGS. 179-183. Zerconopsis remiger (Kramer). Fig. 179, dorsum of female. Fig. 180, venter of female. Fig. 181, chelicera of female. Fig. 182, ventri-anal shield of male. Fig. 183, chelicera of male. 94 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) Zerconopsis muestairi (Schweizer) comb. nov. Lasioseius mustairi Schweizer, J., 1949, Rec. Rech. sci. Pare Nat. Suisse N.F. 2 : 50. FEMALE. Dorsal shield (585-630 fi long X 315-378 /* wide) with a lateral incision anterior to seta Si ; lightly reticulated anteriorly and entirely granular (Text-fig. 184). " Anterior dorsal shield " with nineteen pairs of setae of which one pair is paddle-like, remainder simple ; verticals relatively long and well separated. " Pos- terior dorsal shield " with fourteen pairs of setae of which two pairs are paddle-like, FIGS. 184-188. Zerconopsis muestairi (Schweizer). Fig. 184, dorsum of female. Fig. 185, venter of female. Fig. 186, tectum of female. Fig. 187. ventri-anal shield of male. ] { 188, chelicera of male. THE PLATYSEIINAE (MESOSTIGMATA : ACEOSEJIDAE) 95 the remainder simple ; J5 are the shortest. The distribution and relative lengths of the dorsal setae and the form of the dorsal shield are shown in the Text-fig. Tritosternum with a narrow base and pilose laciniae. Sternal shield with faint sculpturing and bearing three pairs of simple setae (Text-fig. 185). Genital shield also with faint markings, and bearing a single pair of setae. Ventri-anal shield wider than long (180-223 /* l n g X 240-270 /* wide), reticulated in its anterior half and bearing thirteen simple setae. Between the genital and ventri-anal shields lie six platelets. Stigma situated between coxae III and IV with the peritreme not extending posterior to the stigma. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 186) three-pronged and typical of the genus. The chelicerae are figured by Schweizer (1949). Leg I (432-504 IJL long) with the tarsus (118-132 /*) longer than the tibia (68-75 /*). Claws on leg I distinct, pulvillus small ; tarsal setae fine, those on other segments stouter. Tarsi II-IV with a pair of lanceolate setae ; median lobes of pulvilli rounded apically. MALE. Dorsal shield (467-498 /* long x 252-289 ju, wide) with chaetotaxy and ornamentation similar to the female. Sterniti-genital shield with five pairs of simple setae. Ventri-anal shield with nineteen simple setae (Text-fig. 187). The gnathosoma, tectum, pedipalps and legs are typical. Leg I (326-332 fi long) with the tarsus 108-116 /* and the tibia 63-65 /*. The spermatophoral process and chelicera are shown in Text-fig. 188. LOCALITY. This species is known only from the Swiss National Park. We have examined five females and three males from the type series. Zerconopsis michaeli sp. nov. FEMALE. Dorsal shield (498 fi long x 253 fi wide) with a heavy distinct pattern of depressions ; lateral margins irregular, posterior margin crenate (Text-fig. 189). " Anterior dorsal shield " with nineteen pairs of setae of which one pair is paddle- like, the remainder simple ; verticals on tubercles and directed anteriorly. " Pos- terior dorsal shield " with fourteen pairs of setae of which two pairs are paddle-like, the remainder simple. The distribution of the setae and the structure and orna- mentation of the dorsal shield are shown in the Text-fig. Tritosternum with a narrow base and pilose laciniae. Sternal shield plain, bearing three pairs of simple setae (Text-fig. 190). Genital shield narrow, setae off the shield. Ventri-anal shield wider than long (160 /* long X 212 fi wide), with a pattern of reticulations and dots, and bearing eleven setae of which the post-anal is long and stout. There are at least two narrow sclerotized platelets between the genital and ventri-anal shields. Stigma situated between coxae III and IV ; no post-stigmal prolongation of the peritreme. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 191) three-pronged and typical of the genus. Chelicerae typical. 9 6 THE PLATYSEIINAE (MESOSTI GM AT A : ACEOSEJIDAE) Leg I (387 fi long) with the tarsus (101 /*) almost twice the length of the tibia (58 X>. Legs II-IV incomplete in the unique specimen, but some of the setae arise from tubercles. MALE. Unknown. LOCALITY. A single female (1930.8.25.1840) from "England" in the A. D. Michael Collection and labelled " Sejus remiger Kramer ". 190 FIGS. 189-191. Zerconopsis michaeli sp. nov., female. Fig. 189, dorsal shield. Fig. 190, venter. Fig. 191, tectum. Zerconopsis decemremiger sp. nov. FEMALE. Dorsal shield (590-600 /* long x 360-382 /* wide) with a dense pattern of depressions, largest around the anterior margin and becoming smaller posteriorly (Text-fig. 192). " Anterior dorsal shield " with twenty pairs of setae of which two pairs are paddle-like, the remainder simple ; verticals separated by about three times the diameter of their bases. " Posterior dorsal shield " with fourteen pairs of setae of which three pairs are paddle-like ; J5 are the shortest. The distribution of the setae and the ornamentation of the dorsal shield are shown in the Text-fig. Tritosternum with a narrow base and pilose laciniae. Sternal shield with faint THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 97 I 14 FIGS. 192-196. Zerconopsis decemremiger sp. nov. Fig. 192, dorsal shield of female. Fig. 193, venter of female. Fig. 194, tectum of female. Fig. 195, ventri-anal shield of male. Fig. 196, chelicera of male. 98 THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) reticulations and bearing three pairs of simple setae (Text-fig. 193). Genital shield reticulated ; genital setae off the shield. Ventri-anal shield wider than long (205- 220 IJL long X 253-263 fi wide), with a conspicuous pattern of small depressions and bearing eleven simple setae. Between the genital and ventri-anal shields lie four small plates. Stigma situated between coxae III and IV ; peritreme without post-stigmal prolongation. Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum three-pronged and typical of Zerconop- sis (Text-fig. 194) : chelicerae also typical. Leg I (434 /* long) with the tarsus (m-ii6 /*) longer than the tibia (68-70 /*). Claws on leg I small ; tarsal setae fine, those on remaining segments somewhat stouter and arising mainly from small tubercles. Tarsi II-IV with a pair of lanceo- late setae. Ambulacra with median lobes of pulvilli rounded apically. MALE. With dorsal shield (507-550 /* long x 289-330 fi wide) essentially the same as the female. Sterniti-genital shield with five pairs of simple setae. Ventri- anal shield (Text-fig. 195) similar in ornamentation to the female and bearing nineteen simple setae. The gnathosoma, tectum, pedipalps and legs are similar to those of the female. Leg I (434 fi long) with the tarsus (111-113 A) longer than the tibia (68-70 /*). The spermatophoral process and chelicera are shown in Text-fig. 196. LOCALITY. Hungary. The holotype female (1959.1.20.177), allotype male (1959.1.20.178), four female and two male paratypes (1959.1.20.179-184) from Herkulesfurdo, April- June, 1938 ; and four female and two male paratypes from Gyertyanliget, 6-i7th August, 1940, sent to us by Dr. J. Balogh, Budapest. Zerconopsis labradorensis sp. nov. FEMALE. Dorsal shield (581-609 fi long x 299-320 /* wide) with a lateral incision anterior to seta Si, reticulated antero-laterally and the remainder granulate (Text- fig. 197). " Anterior dorsal shield " with twenty-one pairs of setae of which one pair is paddle-like, the remainder simple ; vertical setae with their bases two diameters apart. " Posterior dorsal shield " with fourteen pairs of setae of which two pairs are paddle-like ; J5 are the shortest. The distribution of the setae and the form of the dorsal shield are shown in the Text-fig. Tritosternum with a narrow base and a pair of pilose laciniae. Sternal shield almost without markings, and bearing three pairs of simple setae (Text-fig. 198). Genital shield plain ; setae off the shield. Ventri-anal shield wider than long (177- 215 /* long X 253-260 fi wide), reticulated anteriorly and granulate posteriorly, and bearing fifteen simple setae. Between the genital and ventri-anal shields lie six small sclerotized plates. Stigma between coxae III and IV ; peritreme without post-stigmal prolongation (Text-fig. 199). Metapodal plates small. Venter of gnathosoma with rostral and internal palptrochanter setae long, whip- like. All setae on pedipalp simple. Tectum (Text-fig. 200) three-pronged ; cheli- cerae typical (Text-fig. 201). THE PLATYSEIINAE (MESOSTIGM AT A : ACEOSEJIDAE) 99 FIGS. 197-204. Zerconopsis labradorensis sp. nov. Fig. 197, dorsum of female. Fig. 198, venter of female. Fig. 199, peritrematal shield of female. Fig. 200, tectum of female. Fig. 201, chelicera of female. Fig. 202, tarsus II of female. Fig. 203, venter of male. Fig. 204, chelicera of male. loo THE PLATYSEIINAE (MESOSTIGM ATA : ACEOSEJIDAE) Leg I (462-502 fjb long) with the tarsus (124-134 fi) twice the length of the tibia (65-73 fi) ; tarsal claws small ; setae fine, those on remaining segments shorter and stouter. Tarsi II-IV (Text-fig. 202) with a pair of lanceolate setae ; ambulacra with median lobes of pulvilli rounded apically. MALE. Dorsal shield (488 /* long x 238 fi wide) essentially the same as in the female. Sterniti-genital shield with five pairs of simple setae. Ventri-anal shield (Text-fig 203) similar in ornamentation to the female and bearing nineteen simple setae. The gnathosoma, tectum, pedipalps and legs are similar to those of the female. Leg I (462 ju, long) with the tarsus (124 fi) twice as long as the tibia (65 /*). The spermatophoral process of the chelicera is shown in Text-fig. 204. LOCALITY. Labrador. The holotype female (1959.1.20.185), allotype male (1959.1.20.186) and six paratype females (1959.1.20.187-192) from wet willow humus, West Carter Basin, 4-17 . viii . 1958, collected by P. N. Lawrence during the British Schools' Exploring Society Expedition. SUMMARY 1. This paper deals with the external morphology and classification of the Platy- seiinae. Four genera, namely, Sejus C. L. Koch (syn. Cheiroseius, Episeius and Episeiella), Platyseius Berlese, Zerconopsis Hull, and Plesiosejus gen. nov. are recognized. Keys are given to the species represented in the Collections of the British Museum (Natural History). 2. The following new synonymy is introduced : Lasioseius (Platyseius) capillatus Berl. = Hypoaspis subglabm Oudms. Paraseius tenuipes Halbert = Ameroseius italicus Berl. Episeiella heteropoda Willm. = Sejus viduus C. L. Koch Episeius montanus Willm. = Ameroseius borealis Berl. Episeius ovaspini Schweizer = Lasioseius (Episeius} glaber var. curtipes Halbt. Parasejus glaber var. minor Tragardh = Epicrius laelaptoides Berl. Lasioseius (Episeius} sphagni Halbt. = Epicrius laelaptoides Berl. 3. The following twenty-seven new species are described and figured : Platyseius jamaicensis ; Platyseius spinosus ; Plesiosejus horridus ; Sejus aciculatus ; S. alstoni ; S. antillanus ; S. areolatus ; S. bellingeri ; S. browningi ; S. cassiteridum ; S. clayi ; S. dromadis ; S. hulli ; S. jamaicensis ; S. kennedyi ; S. neborealis ; S. nepalensis ; S. nodosus ; S. ornatus ; 5. parbatensis ; S. phalangioides ; 5. signatus ; S. spinipes ; 5. tuberculatus ; Zerconopsis decemremiger ; Z. labradorensis and Z. michaeli. REFERENCES BERLESE, A. 1882-1903. Acari, myriapoda et scorpiones hucusque in Italia reperta. Portici et Padua. 1904. Acari nuovi II. Redia, 1 : 258-280. 1905. Acari nuovi V. Ibid. 2 : 231-238. 1910. Acari nuovi VI. Ibid. 6 : tav. 19, figs. 35, 350. 1910. Lista di nuove specie e nuovi generi di Acari. Ibid. 6 : 243-271. THE PLATYSEIINAE (MESOSTI GM AT A : ACEOSEJIDAE) 101 BERLESE, A. 1913. Acari nuovi VII-VIII. Ibid. 9 : 77-111. 1916. Centuria prima di Acari nuovi. Ibid. 12 : 19-67. BUITENDIJK, A. M. 1945. Voorloopige Catalogus van de Acari in de Collectie-Oudemans. Zool. Med. 23 : 281-391. EVANS, G. O. 1957. An introduction to the British Mesostigmata (Acarina) with keys to families and genera. /. Linn. Soc. Land. (Zool.) 43 : 203-259. 1958. A revision of the British Aceosejinae (Acarina : Mesostigmata). Proc. zool. Soc. Lond. 131 : 177-229. FRANZ, H. 1943. Die Landtierwelt der Mittleren Hohen Tauern. Denkschr. Akad. Wiss. Wien, 107 : 79-119. HALBERT, J. N. 1915. Clare Island Survey Part 3gii Acarinida ii Terrestrial and marine Acarina. Proc. R. Irish Acad. 31 : 45-136. 1923. Notes on Acari with descriptions of new species. /. Linn. Soc. Lond. (Zool.) 35 : 363-392. HIRSCHMANN, W. 1957- Acarologie Gangsystematik der Parasitiformes Teil i. Rumpf- behaarung und Ruckenflachen. Schriftenreihe fur vergleichende Milbenkunde. Fiirth/ Bay : 1-20 i-v, pis. 1-26. HULL, J. E. 1918. Terrestrial acari of the Tyne Province. Trans, nat. Hist. Soc. Northumb. (n.s.) 5 : 13-88. KOCH, C. L. 1836-1844. Deutschlands Crustacean, Myriapoden und Arachniden. Regens- burg. 1837-1850. Ubersicht des Arachnidensy stems. Niirnberg. KRAMER, P. 1876. Zur Naturgeschichte einiger Gattungen aus der Familie der Gamasiden. Arch. Naturg. 42 : 46-105. OUDEMANS, A. C. 1902. Acariden von Borkum und Wangeroog. Abh. nat. Ver. Bremen, 18 : 77-98. 1903. Acarologische Aanteekeningen, VI. Ent. Ber. 1 : 83-88. 1929. Kritisch Historisch Overzicht der Acarologie, Leiden, 2 : 87 1936. Ibid 3 A : 1-430. SCHWEIZER, J. 1922. Beitrag zur Kenntnis der terrestrischen Milbenfauna der Schweiz. Verh. Naturf. Ges. Basel, 33 : 23-112. 1924. Beitrage zur Kenntnis der Tierwelt norddeutscher Quellgebiete. Acarina (land- milben). Arch, fur Hydrobiol. 15 : 125-132. 1949. Die Landmilben des Schweizerischen Nationalparkes. i. Parasitiformes. Res. Rech. sci. Pare Nat. Suisse, N.F. 2 : 1-99. SELLNICK, M. 1944. Zercon C. L. Koch. A cari-B latter fur Milbenkunde. Konigsberg, No. 5 : 30-41. TRAGARDH, I. 1910. Acariden aus dem Sarekgebirge. Naturw. Untersuch. Sarekgeb. 4 : 375- 586. 1946. Outlines of a new classification of the Mesostigmata (Acarina) based on comparative morphological data. Acta Univ. Lund, N.F. Avd. 2, 42, 4 : 1-32. VITZTHUM, H. G. 1931. Terristrische Acarinen (unter Ausschluss der Oribatiden und Ixodiden) der Deutschen Limnologischen Sunda-Expedition. Arch, fur Hydrobiol., Suppl., 9 : 59- 134- WILLMANN, C. 1938. Beitrag zur Kenntnis der Acarofauna des Komitates Bars. Ann. Hist. nat. Mus. Hung. 31 : 144-172. 1949. Beitrage zur Kenntnis des Salzgebietes von Ciechocinek. Veroff. Mus. Nat. Bremen, No. lA : 106-135. 1952. Die Milbenfauna der Nordsee-Insel Wangerooge. Veroff. Inst. Meeresf. Bremer- haven, 1 : 139-186. 1953. Neue Milben aus den ostlichen Alpen. SB. ost. Akad. Wiss. 162 : 449-5 J 9- 9 6t BRITISH SLUGS (PULMONATA ; TESTACELLIDAE, ARIONIDAE, LIMACIDAE) H. E. QUICK BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) ZOOLOGY Vol. 6 No. 3 LONDON: 1960 BRITISH SLUGS (PULMONATA ; TESTACELLIDAE, ARIONIDAE, LIMACIDAE) BY H. E. QUICK Pp. 103-226 ; 2 Plates ; 19 Text-figures ; 23 Maps BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) ZOOLOGY Vol. 6 No. 3 LONDON: 1960 THE BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY), instituted in 1949, is issued in five series, corresponding to the Departments of the Museum, and an Historical series. Parts will appear at irregular intervals as they become ready. Volumes will contain about three or four hundred pages, and will not necessarily be completed within one calendar year. This paper is Vol. 6, No. 3 of the Zoological series. Trustees of the British Museum, 1960 PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM Issued March, 1960 Price Forty- five Shillings BRITISH SLUGS (PULMONATA ; TESTACELLIDAE, ARIONIDAE, LIMACIDAE) By H. E. QUICK CONTENTS INTRODUCTION ......... Arrangement ........ Acknowledgments ........ NATIVE AND NATURALIZED SPECIES . Order Stylommatophora . ...... Superfamily Oleacinacea ..... Family Testacellidae ..... TESTACELLA Draparnaud Testacella maugei Ferussac Testacella haliotidea Draparnaud Testacella scutitlum Sowerby Superfamily Endodontacea ..... Family Arionidae ...... Subfamily Arioninae ..... GEOMA LA C US Allman Geomalacus maculosus Allman ARION Ferussac .... Arion intermedius Normand . A rion fasciatus (Nilsson) Arion hortensis Ferussac Arion subfuscus (Draparnaud) Arion lusitanicus Mabille Avion ater ater (Linnaeus) Arion ater rufus (Linnaeus) . Superfamily Zonitacea ...... Family Limacidae ...... Subfamily Parmacellinae .... MILAX Gray Milax gagates (Draparnaud) . Milax cf. insularis (Lessona & Pollonera) Milax sowerbyi (Ferussac) Milax budapestensis (Hazay) ZOOL. 6, 3. 106 BRITISH SLUGS Page Subfamily Limacinae . . . . . .163 AGRIOLIMAX Morch 163 Agriolimax reticulatus (Miiller) . . . .164 Agriolimax agrestis (Linnaeus) . . . .170 Agriolimax laevis (Miiller) . . . . .172 Agriolimax caruanae Pollonera . . . .175 LIMAX Linnaeus '> .180 Limax tenellus Miiller . . . . . .180 Limax flavus Linnaeus . . . . .184 Limax cinereoniger Wolf . . . . .187 Limax maximus Linnaeus . . . . igi LEHMANNIA Heynemann . . . .193 Lehmannia marginata (Miiller) . . . ..194 GREENHOUSE ALIENS ......... 197 Lehmannia poirieri (Mabille) ........ 197 Limax nyctelius Bourguignat . . . . . . . . 200 FOSSIL SPECIES ........... 202 Limax modioliformis Sandberger ....... 202 ANATOMICAL TERMS .......... 203 DISTRIBUTION ........... 205 REFERENCES ........... 217 INDEX ............. 224 INTRODUCTION No comprehensive work on British slugs has appeared since John William Taylor's classic monograph (1902-07). Besides full information on their nomenclature, systematics and biology, this contains excellent coloured plates, depicting numerous varieties of the eighteen species of slugs which he recognized as British. Besides much information on these species which has become available since 1907, five more species, a subspecies, and two aliens established in British greenhouses must be added to the list. Taylor omitted Arion lusitanicus (p. 135), although it had already been recorded from Britain, and it has since reappeared. Milax budapestensis (p. 160), another species of Milax provisionally referred to M. insularis (p. 156) and Agriolimax caruanae (p. 175) have been recorded ; Agriolimax reticulatus (p. 164) has been shown to be specifically distinct from A. agrestis, and Arion ater rufus (p. 145) to be subspecifically distinct from A. ater. The alien species Lehmannia poirieri (p. 197) and Limax nyctelius (p. 202) have been found in Britain, but only in greenhouses. Two names used by Taylor must be changed : Arion circumscriptus to A.fasciatus (p. 127) and Limax arborum to Lehmannia marginata (p. 194). Two more recent works also deal with all British slugs, though less completely. Ellis (1926) gives monochrome figures but only occasional references to internal anatomy ; while Quick (1949) also gives monochrome figures, and information relating mainly to identification in the field. Among more general works, Kunkel (1916) on the biology of pulmonates, 0kland (1923) on the Arionidae of Norway, and Boycott (1934) on the habits of British land molluscs may be especially mentioned. Much information on courtship and copulation is given by Gerhardt (1933, 1935, 1939 and 1940), on the seasonal abundance and growth of slugs in gardens and fields BRITISH SLUGS 107 by Barnes & Weill (1945, with good coloured plates of garden species), and on their ecology by Thomas (1944) . For full synonymies, reference should be made to Kennard & Woodward (1926), and also to Taylor (1902-07) and Hesse (1926). Only the more important synonyms are quoted below. The group of naked pulmonates termed slugs is highly polyphyletic in origin. British slugs belong to the three families Testacellidae, Arionidae and Limacidae, which have evidently been derived from shelled Oleacinids, Endodontids and Zonitids respectively. Arrangement Information is given in the same sequence for each species (except that the shell is described before the external variations for Testacella) under the following headings, any of which may be omitted. Notes Radula First British record Alimentary system Diagnostic features Reproductive system External appearance Spermatophore External variation Mating Shell Development Pallial organs Behaviour Pedal gland Ecology Retractor muscles Distribution Nervous system Fossil record Jaw Material examined The anatomical terms used in the descriptions are explained by means of a glossary and semi-diagrammatic figures on p. 203. Distributions in the British Isles are shown on vice-comital maps (p. 205), as well as being briefly described under " distribution ". Acknowledgments I wish to thank the following. The Trustees of the British Museum for financial assistance, and Dr. H. W. Parker, C.B.E. for access to the zoological collections of the British Museum (Natural History). Mr. A. E. Ellis for preparing the maps. M. J. M. Gaillard for information and specimens from the Museum National d'His- toire Naturelle, Paris. Mr. I. C. J. Galbraith for editorial assistance. Dr. H. Loh- mander for information on Scandinavian slugs. Dr. O. E. Paget for information from the Naturliistorisches Museum, Vienna. Dr. W. J. Rees for valuable advice. Mr. H. O. Ricketts for much help in connection with material in the B.M. (N.H.), and for his care in preparing the bibliography and index. The late Mr. Hugh Watson for much helpful correspondence. The many correspondents who have helped from time to time by providing specimens or information, and especially Dr. W. Adam, Dr. C. O. van Regteren Altena, Mr. D. Aten, Dr. H. F. Barnes, Dr. A. J. Cain, Mr. A. E. Ellis, Dr. L. Forcart, Dr. W. O. Gregg, Dr. P. Makings, Dr. A. D. J. Meeuse, Dr. Nils Odhner, Dr. A. W. Stelfox, Mr. Abu Teira, Mrs. M. Vincent, and Dr. M. H. Williamson. io8 BRITISH SLUGS NATIVE AND NATURALIZED SPECIES Order STYLOMMATOPHORA Pulmonate mollusca bearing eyes at the apex of retractile tentacles. Superfamily OLEACINACEA Jaw rudimentary or absent, radular teeth aculeate, shell turreted or auriform. Carnivorous. Family TESTACELLIDAE Shell small, auriform, situated at the posterior end of the body, covering the pallial organs. The upper tentacles (ommatophores) are not bulbous at the apex. There is no caudal mucus gland. A pair of lateral grooves with side branches directed obliquely upwards and forwards, and downwards and forwards, arises from a peri- pallial groove. The pedal mucus gland lies free in the body cavity. The cerebral commissure is very short, and the cerebro-pleural and cerebro-pedal commissures long. There is no jaw. The buccal bulb is enormous. The long narrow radular teeth, barbed at the apex, are disposed in transverse V-shaped rows, and a central tooth may be absent. The stomach is feebly developed and the anus lies just within the pulmonary cavity posteriorly. The kidney is without a secondary ureter. An osphradium is said to be present in a groove in the floor of the mantle cavity (Plate, 1891). The vagina is without accessory glands, and the right ocular retractor muscle passes forwards between the penis and vagina. Testacella is carnivorous, feeding on earth-worms and occasionally on other slugs, and is largely subterranean in habit. Genus TESTACELLA Draparnaud, 1801 Type species Testacella haliotidea Draparnaud, 1801. The sole genus, with the characters of the family. Through adaptation to a life spent largely underground, and a diet of earth-worms, the structure of Testacella has been profoundly modified. The relatively large shell and mantle cavity of other snails have been greatly reduced in size, and the body anterior to these structures elongated to accommodate the enormous buccal bulb with its powerful muscles and barbed radular teeth. The backwards shift of the pallial region is accompanied by a clockwise rotation of 180, so that the heart and pericardium lie on the right side of the kidney with the ventricle in front of the auricle. The normal backwardly- directed loop of the intestine is obliterated, and the rectum runs backwards instead of forwards to the anus (beside the pulmonary orifice, at the rear). It is convenient to gather together the available information on the life history of all the three British species of Testacella. A recent paper by Stokes (1958) gives further information, supplementing that of Barnes & Stokes (1951). Mating Little is known, but Gerhart (1940 : 579) reports that while unpacking a container he found a pair of T, scutulum in coitus in the moss, and accidentally separated them. BRITISH SLUGS 109 The penes were bluish-white, translucent, elongated, dorso-ventrally flattened cones, withdrawn from the adjacent vaginal openings. No appendix was visible, and the penes were of the simplest type occurring in land pulmonates. They quickly disappeared within the owners' bodies, and no more was to be seen. Barnes & Stokes (1951) found that the coitus of T. haliotidea and T. scutulum took place under the surface of the soil in their containers, the animals lying head to head : they do not mention any visible everted organs. Chemin (1939^ and b) reports self-fertilization in T. haliotidea isolated when young. Development The eggs are ellipsoidal, with a white calcareous shell which becomes yellow, and are laid underground. Those of the three British species are distinguished only by differences in size 15x4 mm for T. maugei, 7x4 mm for T. haliotidea, and 4x3 mm for T. scutulum. Barnes & Stokes confirm the old statement that they explode when placed on a warm hand. The eggs of T. maugei are laid in groups of 8-15 during the summer months, those of T. haliotidea and T. scutulum in captivity (Barnes & Stokes, 1951) in batches of 2-14 in March, 54-95 days after mating. Taylor (1902-07) records the time of development as 30-35 days for T. maugei, 20-36 days for T. scutulum and (quoting Gassies, 1849) 10-22 days for T. haliotidea. However, Barnes & Stokes found that embryonic development takes much longer than this for the latter two species : 144-201 days, or five to six months. Like all our slugs and some, perhaps all, of the shell-bearing Stylommatophora except Succinea (which lacks a caudal vesicle), Testacella exhibits in the middle and late stages of development a haemocoelic cephalic vesicle protruding beneath the mantle over the head, containing part of the viscera ; and a caudal haemocoelic vesicle projecting beyond the tail, which contains only haemocoelic fluid and cor- puscles. The caudal vesicle varies in shape from genus to genus (see Text-fig. 18). In Testacella it is a flattened bilobed or broadly cordate sac (Text-figs, i D and 18 c). The two vesicles pulsate, expanding and contracting alternately so that haemocoelic fluid is driven back and forth, at a rate depending on the temperature. The vesicles may have an excretory or a respiratory function. The cephalic vesicle is withdrawn with its contents into the body, and shortly before hatching the caudal vesicle also shrinks and disappears. In Testacella, with its posterior mantle, the cephalic vesicle does not extend over the head (at any rate in the later embryonic stages). Behaviour It has been noted (Adams, 1941) that dust sprinkled on Testacella leads to copious discharge of fluid which washes it away. Another phenomenon does not seem to have been recorded. When lightly irritated, Testacella maugei partially contracts, and sometimes a forcible discharge of air and froth occurs in the middle line from under the front of the mantle edge, with a distinct high-pitched hissing sound. Presumably a communication to the lung cavity exists, and air is expelled by closure of the pulmonary orifice and muscular contraction. No duct is apparent on gross dissection, but serial section of the area show spongy tissue leading to the anterior no BRITISH SLUGS expansions of the pulmonary cavity, through which air might be expelled. In its underground travels, or if dragged into a burrow by an attacked earth-worm, it is easy to imagine that earth could become impacted under the mantle border, and that the forcible expulsion of air and fluid would serve to dislodge it. Ecology Mostly to be found in gardens, allotments and other cultivated ground. During the day Testacella remains underground, retreating deeper in dry weather but some- times hiding under stones and herbage in damp weather ; while at night it crawls freely on the surface. In the winter it hibernates in a strongly contracted state, in an underground cell. On slowly approaching a worm, the slug shoots out its radula and impales its prey at one end or in the middle, and engulfs it within a few minutes. Another worm may be eaten after a day or two. The faeces are very small in bulk and contain discarded radular teeth, fragments of worm cuticle and setae, and sometimes small white bodies which may be from the calcareous oesophageal glands of worms. Testacella is also said to eat other slugs. Testacella maugei Ferussac, 1819 Testacella maugei Ferussac, 1819 : 94, pi. 8, figs. 10 and 12. Teneriffe. Testacella aurigaster Watson, 1915 : 221 (from Layard MS.). Notes The type was found in 1796 by M. Mauge ; who died before publishing an account. According to Turton (1831 : 27), it was sent in 1812 from Dr. Leach at Bristol to Ferussac. T. aurigaster refers to this species, introduced into South Africa (Watson, 1915 : 221). First British record By Ferussac (1819). Diagnostic features Pear-shaped appearance (body widest behind) ; shell large (14 X 7 mm) ; two median lines of dorsal tubercles conspicuous, especially in the young ; lateral grooves wide (5 mm) apart at origin. Buccal bulb lacks lateral retractors ; cephalic retractors arise asymmetrically, from left side. Penis swollen posteriorly, lacks the flagellum of T. haliotidea ; penial retractor arises from body-wall about two- thirds of the way back ; vas deferens convoluted near free oviduct ; spermatheca duct long and slender, swollen proximally. External appearance (PI. I, fig. 13) Length when extended, 6-10 cm. The most bulky part of the body lies behind the centre. The lateral grooves are separated by about 5 mm at their origin from the peri-pallial groove, and each gives rise to about fourteen dorsal and ventral BRITISH SLUGS in grooves directed obliquely forwards, which subdivide to produce the reticulate surface pattern. The row of tubercles on each side of the median dorsal line is more prominent than the other dorsal rows, especially in the young. The upper tentacles, bearing the small black eyes, are not bulbous at the apex, and the lower tentacles are short. The true pedal groove is only distinct for a few millimetres at the front of the foot fringe, but a peripodial groove above this runs to the tail. There is no caudal mucus gland. When crawling on a glass plate, the yellow sole is seen to be obscurely tripartite. The mucus is clear and viscid, drawing out into thin threads. The body is usually some shade of brown more or less sprinkled with darker spots, paler on the sides, and the sole is yellow or pink. The mantle is speckled with black, and the paler margin slightly overlaps the shell. The posterior respiratory orifice is bounded by the right and left mantle lobes. Shell (Text-fig, i A) The shell measures about 14 X 7 mm, and has a brown periostracum, often abraded. It is more convex than the shells of the other two species, and the columella does not show the same callous enlargement at the hinder end. The crescentic muscle scar is visible on the under surface. External variation Variety aperta Taylor (1902) has the shell wider and flatter than normal. Varieties albina, griseonigrescens, viridans and griseorubescens Gassies & Fischer (1856), nigra Collinge (1898) and aurea Taylor (1902) are colour varieties, whose charac- teristics are suggested by their names. P allied organs (Text-figs. 2 D and F) The respiratory cavity, bounded by the right and left mantle lobes, leads to the pulmonary chamber, which is bounded by spongy vascular tissue. Anterior to this, the chamber is prolonged forwards as thin -walled air sacs projecting into the visceral cavity. The somewhat quadrate kidney, opening without a secondary ureter at the back of the chamber, lies above and in front of the pulmonary chamber. The pericardium lies to the right of the kidney and the ventricle is anterior to the auricle, and both branches of the aorta run forwards. The rectum runs obliquely in the pulmonary chamber to terminate in the anus just above and on the left of the respiratory orifice. The kidney projects over the apex of the left liver lobe. An osphradium is represented by a ridge of cells in the floor of the respiratory chamber, and is innervated from the right visceral ganglion (Plate, 1891). Retractor muscles (Text-fig, i E) Both the cephalic retractor muscles arise from the body-wall on the left side. The right ocular retractor passes between the penis and the vagina, and a branch takes the same course to the side of the head. The slender penial retractor arises from the right body wall about two-thirds of the way back, and not from the posterior end as it does in T. haliotidea and T. scutulum. 112 BRITISH SLUGS FIG. i. Testacella. Reproductive organs (x 3-3), shell (x 2). A. T. maugei shell below. B. T. haliotidea shell right, below. C. T. scutulum shell right, above. D. T. scutulum advanced embryo ( x 6-7) showing cephalic vesicle in front of shell and caudal vesicle posteriorly. E. T, maugei buccal bulb and ocular retractors. BRITISH SLUGS Nervous system (Text-fig. 2 E) The cerebral commissure is very short, and the cerebro-pleural and cerebro-pedal commissures are long to embrace the large buccal bulb. The buccal ganglia are large. The five visceral ganglia are close together, but not fused. Radula (Text-fig. 2 A) In each row, sixteen aculeate barbed teeth on each side of a small median tooth increase in size up to the penultimate one, while the sixteenth is much smaller. There are about fifty V-shaped rows. B FIG. 2. Testacella. Representative radular teeth ( x 67). A. T. maugei showing central tooth. B. T. haliotidea showing absence of central tooth. C. T. scu- tulum showing absence of central tooth. T. maugei. D. Posterior end of body ( x 3-3) with shell removed and right mantle lobe reflected to expose respiratory orifice. E. Central nervous system, showing buccal ganglia (black) posterior to cerebral ganglia when animal is contracted, F. Pallial region, viewed as if shell were transparent. H4 BRITISH SLUGS Alimentary system The buccal bulb, which is large but does not extend as far back as in T. haliotidea and T. scutulum, lacks lateral muscles but has a bundle of from two to four pairs of powerful muscles at the posterior end, attached to the diaphragm towards the left of the mid-line (Text-fig. I E). The small stomach is scarcely wider than the oesophagus and intestine. It receives the right and left liver ducts, and the left liver lobe forms the apex of the visceral mass. The intestine makes one forwardly- directed loop, and the long rectum runs backwards to the anus, close to the respiratory orifice. Reproductive system (Text-fig. I A) The reproductive organs are simple. The pale ovotestis lies at the apex of the visceral mass between the right and left lobes of the liver. The slightly sinuous hermaphrodite duct becomes slender and folded before entering the long narrow albumen gland, and bears a small seminal vesicle. The convoluted vas deferens, arising from the yellow ribbon-like prostate, runs forwards beside the free oviduct and then turns backwards, beneath the right ocular retractor to the apex of the penis. The penis is about 9 mm long, slender in front and dilated posteriorly and often folded over forwards. The mucous membrane is papillate at the apex and longitudinally ridged beyond, and there is no penial papilla. There is no caecum or flagellum. The penial retractor, arising from the right body wall about two- thirds of the way back, is inserted at the apex of the penis. The atrium is short and opens below the right upper tentacle. The free oviduct and vagina are wider than the penis. The long slender spermatheca duct is dilated at its origin from the oviduct, and enters the spermatheca sac laterally. The mucous membrane of the duct is longitudinally ridged, the ridges being more prominent in the bulbous part of the duct. Mating, Development, Behaviour, Ecology See pp. 108-110. The eggs measure 5x4 mm. Distribution (Map i) T. maugei is the most westerly of the three British species of Testacella, known from Tangier, south-western Spain, Portugal, Brittany, Dieppe and the Atlantic isles (and introduced into North America and South Africa) . In England and Wales it occurs west of a line from Cheshire to Middlesex, and in Ireland south-east of a line from Dublin to Cork. It is probably truly native only in the south-west. Fossil record Holocene and Recent. Material examined Living specimens from Singleton Park Botanical Gardens, Swansea, Glamorgan. Spirit material from various British localities, the Azores and Madeira. BRITISH SLUGS 115 Testacella haliotidea Draparnaud, 1801 Testacella haliotidea Draparnaud, 1801 : 99. ? Montpellier. Testacella europea de Roissy, 1805, 5 : 252. First British record By Lukis (1834), fr m Guernsey. Diagnostic features Less bulky posteriorly, when extended, than T. maugei ; shell much smaller, (7x5 mm), columella somewhat truncate anteriorly, with conspicuous callous enlargement posteriorly ; dorsal tubercles not especially prominent ; lateral grooves close together at origin. Buccal bulb with powerful lateral retractors ; cephalic retractors arise symmetrically. Radula lacks a central tooth, apophyses of marginal teeth nearly central. Penis with flagellum and short apical caecum ; penial retractor arises from diaphragm at posterior end of body ; spermatheca duct short and bulbous. External appearance (PI. i, fig. 10) Length when extended, 8-12 cm. The lateral grooves are close together at their origin from the peri-pallial groove. Colour usually dull greyish-yellow, with a pale sole and foot fringe. Shell (Text-fig, i B) Measures about 7x5 mm, convexly auriform, triangular ; brown periostracum usually much abraded. Columella usually slightly truncate anteriorly, and expanded to a rounded callus posteriorly. External variation In var. trigona Gassies & Fischer (1856) the shell is thicker and the right margin expanded, in var. major G. & F. the shell is larger (11-5 X 7 mm). The body is yellow in var. flavescens Moquin-Tandon (1855), and whitish in var. albino, Moquin- Tandon. Pallial organs As in T. maugei. Retractor muscles The cephalic retractor muscles arise symmetrically on each side of the body-wall about two-thirds of the way back, and not from the left side only as in T. maugei. The long, slender penial retractor arises dorsally at the hind end of the body. Nervous system > As in T. maugei. n6 BRITISH SLUGS Radula (Text-fig. 2 B) The median tooth is vestigial or absent. On each side, eighteen barbed aculeate teeth gradually enlarge up to the penultimate one, while the eighteenth is shorter. The lateral apophysis is nearly midway between base and apex (especially towards the margin of the radula), while in T. scutulum it is nearer the basal end. There are about fifty V-shaped rows. Alimentary system The large buccal bulb is longer than in T. maugei and has, in addition to the bundle of posterior muscles attached to the diaphragm, a series of ten to fifteen pairs of lateral muscles attached to the posterior half of the bulb and arising from the left body-wall. The relations of the liver lobes, intestine and rectum are as in T. maugei. Reproductive system (Text-fig, i B) Compared with T. maugei, the central portion of the hermaphrodite duct is longer and more folded, the penis is slighly enlarged at the entrance of the vas deferens, and opposite this point there is a short blunt caecum. There is also a flagellum, which varies in length but may be two-thirds as long as the penis, from the apex of which a long slender retractor muscle runs to the diaphragm at the posterior end of the body. There is no penial papilla, and the mucous membrane is papillate. The spermatheca duct is short, wide and bulbous with the mucous membrane strongly folded longitudinally, and the sac is oval. Mating, Development, Behaviour, Ecology See pp. 108-110. The eggs measure 7x4 mm, and so are considerably larger than those of T. scutulum. Distribution (Map 2) T. haliotidea is the most widely distributed species, ranging from the Atlantic isles to the Balkans, and from the North African coast to south Scotland. It probably occurs in every county in Britain up to Stirling, and in the south-eastern and southern counties of Ireland. Fossil record Holocene and Recent. Material examined Living specimens from Henley-on-Thames, Bedford and Cambridge. Spirit material from Britain, France and Majorca. BRITISH SLUGS 117 Testacella scutulum Sowerby, 1820 Testacella scutulum Sowerby, 1820 : pi. 159, figs. 3-6. Kennington Road, Lambeth, Surrey. Notes Taylor (1902-07) considers T. bisulcata Risso (1826) as a variety of this species. Plate (1891) and Hoffman (1925), however, consider it to be quite distinct. Plate's figure, copied by Hoffman, shows a flagellum from the anterior end of the penis, and a tubular connection from the vagina to the apex of the flagellum. This most unusual arrangement is said to be confirmed by serial sections. First British record By Sowerby (1820). Diagnostic features Resembles T. haliotidea, but differs in the following. Shell smaller (6 X 3-5 mm) and flatter ; animal yellow in colour, speckled with brown. Apophyses of marginal radular teeth more basal. Penis lacks caecum and flagellum ; free oviduct shorter than vagina ; spermatheca duct longer and narrower (but quite different from that of T. maugei). External appearance Length when extended, 8-12 cm. The lateral grooves are said to be confluent for about i mm at their origin from the peri-pallial groove, but this does not seem to be constant. Colour some shade of yellow, more or less sprinkled with brown ; sole and foot fringe brighter yellow. Shell (Text-fig, i c) Smaller than that of T. haliotidea (6 X 3-5 mm), and flatter sometimes even concave. The brown periostracum tends to be retained better than in the other species. The columella is slightly truncate anteriorly and expanded posteriorly, as in T. haliotidea. Young shells of these two species can easily be confused. External variation Most of the varieties mentioned by Taylor (1902-07) refer to continental forms, which may or may not be conspecific with T. scutulum. However, var. aurea Cockerell (1885) presumably refers to this species : it is orange-coloured, with brown mottling and a bright orange foot sole. Pallial organs As in T. maugei and T. haliotidea. n8 BRITISH SLUGS Retractor muscles The cephalic retractors arise symmetrically from the body-wall about half-way back. The penial retractor arises far back, from the diaphragm. Nervous system As in T. maugei and T. haliotidea. Radula (Text-fig. 2 c) As in T. haliotidea, the median tooth is absent and there are eighteen teeth on each side of the mid-line ; but in the outer marginal teeth the apophyses are nearer the bases. There are about forty-five V-shaped rows. Alimentary system The buccal bulb has three or four strong muscles from the diaphragm to its posterior end, and the hinder half has five to ten pairs of lateral muscles attached to the left body-wall. The relations of the liver lobes, intestine and rectum are as in T. maugei and T. haliotidea. Reproductive system (Text-fig. I c) The ovotestis, albumen gland, prostate and oviduct resemble those of T. haliotidea, but the free oviduct is relatively shorter and the vagina longer. The spermatheca duct is intermediate in length and breadth between those of T. haliotidea and T. maugei. .The penis is cylindrical, without dilatations or flagellum, and the retractor muscle arises far back from the diaphragm. The penial mucous membrane is papillate, and that of the spermatheca thrown into longitudinal folds. Mating, Development, Behaviour, Ecology See pp. 108-110. The eggs are smaller (4x3 mm) than those of the other species, but otherwise similar. Distribution (Map 3) Taylor (1902-07 : 18) apparently treated T. bisulcata Risso (1826) as a variety of T. scutulum, so that his account of the latter's continental distribution is unreliable. In the British Isles, its distribution is almost the same as that of T. haliotidea. Fossil record Recent. Material examined Living specimens from Bedford. Spirit material from Britain and Corsica. BRITISH SLUGS 119 Superfamily ENDODONTACEA Shell spiral depressed, or reduced to a flat plate or mass of granules enclosed by the mantle. A supra-pedal groove is present, and a caudal mucus gland may be present or absent. The jaw is either crescentic and ribbed, or plaited. Marginal radular teeth generally aculeate. The genitalia are simple. Family ARIONIDAE Slug-like animals with the mantle covering only the anterior part of the body, with the respiratory orifice in a slit on the right margin. Shell an oval plate or mass of granules except in Binneya, where it is exposed and spiral. The sole is uniform or tripartite. The kidney surrounds the pericardium. An epiphallus is present. The jaw is ribbed (odontognath) , the central radular tooth tricuspid, lateral teeth bicuspid, marginals with short wide basal plates, with long mesocones and with or without ectocones. The Arionidae require relatively high humidity, and dry barren areas are barriers to their dispersal. The family seems to have been derived from Endodontid stock with spiral shells, the cephalic and buccal retractor muscles with a common origin from the columella, and a penial papilla. In the primitive North American genus Binneya, the visceral hump is capped by a spiral Vitrina-like shell, the tail is solid and the retractors have a common origin. Various genera show transitions from this snail-like condition to that of the most modified subfamily, the Arioninae of the western Palaearctic Region. For a discussion of the probable evolution of the other subfamilies and genera, see Pilsbry (1948 : 660-665). Subfamily ARIONINAE Slugs with a wide foot fringe ; caudal mucus gland present ; the shell is reduced to a flattened plate in Geomalacus, and to discrete granules in Arion. The cephalic retractor muscles are widely separated at their origin from the posterior border of the diaphragm. The stomach apex lies behind the posterior loop of the intestine. The ovotestis lies behind all the intestinal loops. There is no penis or vagina, and the oviduct, spermatheca and epiphallus enter the upper atrium separately. Of the British genera, Geomalacus with its solid shell, anterior reproductive orifice, narrower foot fringe, and extreme western distribution, seems to be the more primitive. Genus GEOMALACUS Allman, 1843 Type species Geomalacus maculosus Allman, 1843. Genital orifice below and behind the right upper tentacle ; atrium greatly elong- ated ; genital retractor muscle arising from the dorsal body-wall at the extreme posterior end of the body and inserted into the spermatheca duct ; shell a compact oval calcareous mass. ZOOL. 6, 3. 9 BRITISH SLUGS G. maculosus is the only member of this genus occurring in the British Isles, though one or two more are found with it in the Iberian peninsula. Geomalacus maculosus Allman, 1843 Geomalacus maculosus Allman, 1843 : 851. Lough Caragh, Co. Kerry, Ireland. Notes The types were found by W. Andrews of Dublin in 1842. First British record By Allman (1843). Diagnostic features Distinguished from species of Arion, externally by the anterior situation of the reproductive orifice, narrower median area of the sole, and maculate colour pattern ; and internally by the solid oval shell, greatly elongated atrium, and long genital retractor arising far back from the mid-dorsal line of the body-wall. External appearance (PL i, fig. i) Length when extended about 5-5 cm, but occasionally up to 9 cm. The granulose mantle occupies about one-third of the body, with the respiratory orifice a little in front of the centre of the right border. The reproductive orifice is nearer to the right upper tentacle than to the respiratory orifice. The supra-pedal groove is deep and distinct and the pedal groove indistinct. The caudal mucus gland is a transverse slit. The body shows about twenty-five rows of polygonal tubercles (Text-fig. 3 c). The colour is grey, brown or nearly black, irregularly marked with yellow or white maculations more or less developed. The young have two longitudinal bands on each side, which tend to become obscured in the adult, but sometimes remain. In contrast to Arion, Geomalacus sometimes rolls up like the woodlouse Armadillidium. External variation Var. fasciata Cockerell (1892) retains the banding characteristic of the young animal white or whitish with black or brown markings : mantle with dark marbling and lateral bands, body with a dark subdorsal band along each side. Charles Oldham bred in captivity a crimson form, var. rutilans Oldham (19426), which has not been observed in the wild. The other varieties depend merely on the relative development of dark pigment on a pale ground : var. allmani Heynemann (1873), dark brown or grey with whitish maculations ; var. verkruzeni Heynemann, grey, darker dorsally, with whitish maculations; var. andrewsi Mabille (1867), whitish, overspread with blackish spots. BRITISH SLUGS 121 Shell (Text-fig. 3 i) Variable, but usually solid, oval, convex above and concave below, measuring about 4x3 mm. PaLlial organs (Text-fig. 3 B) The kidney completely surrounds the pericardium, and the cavity is occupied by lamelliform folds. The ventricle lies behind the auricle. The anterior branch of the aorta follows the usual course, arching over and passing beneath the anterior intestinal loop, and running forwards between the visceral and pedal ganglia to supply the anterior end of the body. The posterior aorta runs backwards to the digestive and genital systems. Retractor muscles (Text-fig. 3 B) The right and left cephalic retractor muscles are widely separated at their origin from the diaphragm, behind the kidney. The buccal retractor arises from the dorsal body-wall, a little further back and slightly to the right of the middle line. The right tentacular branch lies to the left of the oviduct and epiphallus, and does not pass between them. Nervous system The cerebral commissure is of medium length. The cerebral ganglia give rise to nerves to the head and lips, the peritentacular nerves, the combined ocular and olfactory nerve, the nerve to the lower tentacle, and on the right side to the genital nerve supplying the epiphallus and vas deferens. The right pleural, visceral and abdominal ganglia are fused together, but just distinguishable, and the same is true of the left pleural and the left visceral ganglia. The pleuro-pedal commissures are very short. The buccal ganglia, as well as supplying the buccal bulb, send a nerve to the salivary glands. Jaw (Text-fig. 3 D) The jaw is about 3 mm across, dark brown, arcuate, and crossed by eight or ten broad ribs which slightly denticulate the upper and lower margins. The number of ribs may be reduced by fusion, and there is sometimes a slight median projection. Radula (Text-fig. 3 E) The radula is about 8 mm long. There are usually about 200 rows of teeth, but the number varies considerably. The central tooth has very small ectocones. The lateral teeth, about twenty in number, have a large mesocone, a small ectocone, and no endocone. The ectocone gets smaller in the outer lateral teeth. In the marginal teeth it descends to the base of the mesocone, and gets larger again as the margin of the radula is approached. 122 BRITISH SLUGS 52. H FIG. 3. Geomalacus maculosus. A. Reproductive organs (x 2-7). B. Head and mantle region (x 1-7) with mantle reflected to the right showing kidney, peri- cardium, rectum, terminations of genital and alimentary systems, origin of pharyngeal and left ocular retractors cut short. C. Polygonal body-tubercles. D. Jaw (x 13). E. Representative radular teeth ( x 330). I. Shell. Avion. Representative radular teeth (x 330). F. A. ater. G. A. lusi- tanicus. H. A. subfuscus. BRITISH SLUGS 123 Alimentary system The oesophagus, after passing through the nerve ring, enlarges to a crop, merging into the stomach which forms the most posterior part of the alimentary canal. The narrower intestine passes far forwards (to the level of the kidney) and then turns back, but does not reach the stomach before it runs forwards again, as the rectum, to end in the anus in the posterior lip of the respiratory orifice. The short ducts of the anterior and posterior lobes of the liver open at the junction of stomach and intestine. Reproductive system (Text-fig. 3 A) The somewhat raspberry-shaped brown ovotestis lies between the upper and lower lobes of the liver, at the apex of the stomach. The pale hermaphrodite duct passes forwards, becoming wider and folded, towards the linguiform albumen gland. It then becomes narrower, runs backwards between the lobes of the albumen gland, and turns sharply forwards, forming a " claw" or seminal vesicle. The common duct is much folded, the prostatic portion showing as a yellow ribbon. The narrower free oviduct enters the lower end of the atrium ; its mucous membrane is thrown into fine longitudinal folds. The lower atrium shows internally a complicated mass of large sinuous folds, and is also remarkable in having a long slender diverticulum with circular folds, extending backwards as far as the albumen gland. The short duct of the globular spermatheca enters the apex of this diverticulum. The vas deferens runs backwards from the free oviduct towards the apex of the atrial diverti- culum, to enter the wider epiphallus which is very long and much coiled, the coils being bound together by connective tissue. The epiphallus enters the atrial diverti- culum close to the spermatheca duct. A long slender retractor muscle, arising from the mid-dorsal line at the posterior end of the body, is inserted at the neck of the spermatheca and apex of the diverticulum. The mucous membrane of the epiphallus shows longitudinal rows of papillae, and that of the spermatheca longitudinal folds. A membrane with a series of muscular bands extends from the atrial diverti- culum to the diaphragm, and similar bands from the lower atrium to the body-wall. Mating This has not been recorded. Development The ellipsoidal eggs are said (Taylor, 1902-07 : 256) to be relatively large, from 8-5 x 4-25 to 6 X 4 mm, and to be white when laid, turning brown. They are laid, in clusters of from 18 to 24, in July and August, and hatch in from six to eight weeks. The young, which mature in the following summer, show two dark bands on each side which fade during growth. Behaviour When irritated, it can roll up like the woodlouse Armadillidium (Taylor, 1902-07 : 257)- 124 BRITISH SLUGS Ecology G. maculosus lives on the bare mountain slopes of Old Red Sandstone in Cork and Kerry, where it browses on the algae, mosses and liverworts which coat the boulders. In captivity it readily feeds on lettuce and carrot, and has been observed to attack small snails such as Vitrina pdlucida. Distribution (Map 4) Portugal, north-western Spain, and Vennes (France). In Britain it is confined to south-western Ireland, in the counties of Cork and Kerry. Fossil record Recent. Material examined Preserved specimens from Glengariff, Co. Cork (August 1931), and other localities, in Cork and Kerry. Genus ARION Ferussac, 1819 Type species Avion empiricorum Ferussac (= Limax ater Linnaeus, 1758). The diagnostic features of the genus are those of the subfamily Arioninae. Differences from Geomalacus are : reproductive orifice immediately below posterior lip of respiratory orifice ; upper atrium not prolonged backwards as a diverticulum ; genital retractor short, arising from diaphragm close to left cephalic retractor, and inserted into both spermatheca duct and free oviduct ; shell reduced to discrete granules ; median area of sole wider. A . intermedius and A . fasciatus seem to be less advanced than the other species, in the absence of a ligula, the limited eversion of the gentalia during coitus (in A. fasciatus at least), and the slightly more anterior position of the reproductive orifice in A . fasciatus. A . hortensis differs strikingly from A . fasciatus and from the larger species, but agrees with A . subfuscus and A . lusitanicus, in having the ligula (or its functional equivalent) in the proximal part of the oviduct. A. lusitanicus is in some respects intermediate between A . subfuscus and A . ater ; while the latter, in which the banding pattern disappears completely in the adults, is probably the least primitive. The various subgenera and sections that have been proposed are not satisfactorily delimited. Hesse (1926 : 64-69) uses the following subgenera : Lochea Moquin- Tandon (1855), for A. ater and A. lusitanicus (though the genitalia of the latter are much more like those of A . subfuscus) ; Mesarion Hesse, for A . subfuscus ; Carinarion Hesse, for A. fasciatus ; Kobeltia Siebert (1873), for A. hortensis ; and Microarion Hesse, for A . intermedius. BRITISH SLUGS 125 Arion intermedius Normand, 1852 Avion intermedius Normand, 1852 : 6. Valenciennes. Arion minimus Simroth, 1885 : 237, pi. 7, fig. 41. First British record By Alder (1848 : 124), as Arion flavus. Diagnostic features Small size, tubercles assume a conical shape with translucent apices when animal contracts, yellow mucus accumulates at each end of foot ; reproductive orifice slightly anterior to respiratory orifice. External appearance (PL i, fig. 7) This is the smallest British Arionid, about 2 cm long when crawling. Its colour varies from yellow to some shade of grey, with the head darker grey or black, and there may or may not be body and mantle bands. All these colour varieties may be found living together. A. intermedius is easily distinguished from the young of larger species by the form of its tubercles, which stand up in little conical eminences with translucent tips when the animal contracts hence the popular name Hedgehog Slug. The pair of mantle bands together form a lyre-shaped figure, and the right band arches over the respiratory orifice and sends a branch down below and behind it. The sides of the body are paler than the back, the foot fringe is yellowish-grey, and just above it there is a row of black dots towards the anterior end. The sole is yellowish-grey, and yellow mucus tends to accumulate at each end of it. The genital orifice is immediately below the slit of the respiratory orifice, and thus is further back than in A . fasciatus but slightly further forward than in the other species. External variation Var. normalis Moquin-Tandon (1855), yellow with blackish head and tentacles ; var. plumbea Collinge (18926), dark grey ; var. brunnea Taylor (1902-07), maroon- brown with darker bands ; var. alba Taylor, almost white. Shell The shell granules are not specifically distinguishable. In calcareous sites they may be aggregated into an irregular mass. Pallial organs As in A. ater (p. 139). Retractor muscles As in A. ater, except that the cephalic retractors do not arise at the same level, but with the right a little further forward than the left ; while the genital retractor 126 BRITISH SLUGS sends a branch to the junction of oviduct and atrium, as well as to the neck of the spermatheca. Nervous system As in A . ater. Jaw About i mm across, arcuate and crossed by seven to ten widely-spaced ribs. Of the usual Arionid shape, and so not like Taylor's figure (1902-07, fig. 248). Radula About 2 mm long, with about 120 transverse rows of teeth. The base of the mesocone of the central tooth is more constricted than in the other species. There are about sixteen lateral and sixteen marginal teeth, each with mesocone and ectocone : they do not have endocones. Formula C.i6.i6 x 120. Alimentary system As in A . ater, except that the visceral mass is less twisted. Reproductive system (Text-fig. 4 H) The deeply pigmented ovotestis lies between the lobes of the liver, and is partly exposed on the surface of the visceral mass. The central part of the pale hermaphro- dite duct is wider and somewhat sinuous, then narrows and runs back on the short linguiform albumen gland and bends sharply forwards, making a " claw " or seminal vesicle. The sperm-oviduct is short, and the free oviduct enters the very short upper atrium without a ligula. The mucous membrane is thrown into five or six low longitudinal folds. The lower atrium is about 2 mm long and smooth internally. The spherical spermatheca is connected to the upper atrium by a very short duct, much dilated at its base. The vas deferens is about 2 mm long, and the epiphallus about the same length. Spermatophore Unknown. Mating Not recorded. Development The ellipsoidal eggs are relatively large (2 X 1-5 to 2 X 2 mm), opaque, white and dotted with calcareous spots. They are laid in the summer and autumn, and hatch in about three weeks. The young at birth are 4 mm long, and easily recogniz- able as miniatures of the adults. BRITISH SLUGS 127 Ecology Common in the moist ground-litter of woods and copses, beneath logs, and at the roots of grass in open fields. Often found feeding on toadstools in the wild, and in captivity readily eats carrot, lettuce and oatmeal. Distribution (Map 5) Portugal, Spain, France, northern Italy, Switzerland, Germany, Scandinavia, Russia, Azores (and introduced into New Zealand, Polynesia and North America). It probably occurs in every vice-county in the British Isles, including islands north- wards to the Orkneys and Shetland. Fossil record Although shell granules of Arion are not recognizable with certainty, they are recorded from the Cromerian onwards. They cannot be assigned specifically. Material examined Living specimens from many parts of England and Wales. Spirit material from Britain, France, Norway and Tahiti. Arion fasciatus (Nilsson, 1822) Limax fasciatus Nilsson, 1822 : 4. ? Sweden. Arion circumscriptus Johnston, 1828 : 76. Notes Collinge (18926) reinstated Nilsson's name, though it has not been adopted by other British authors. Lohmander (1937) also concluded that fasciatus is the valid name, though he continued to use circumscriptus. Nilsson's description of his species leaves no doubt that it is the A. circumscriptus of most authors, and Collinge's use of fasciatus prevents any action being taken to conserve circumscriptus. First British record By Johnston (1828). Diagnostic features Body bell-shaped in transverse section when contracted, mid-dorsal line of tubercles pale and raised, reproductive orifice in front of respiratory orifice, right mantle band arches over respiratory orifice, sole opaque porcelain white ; sperma- theca with short stout duct and long tapered sac, spermatophore coiled anteriorly. External appearance (PI. I, fig. 5) Length when crawling about 3-3-5 cm. Easily distinguished from A. hortensis by the opaque white sole, and by the bell-shaped transverse section of the body 128 BRITISH SLUGS when contracted (caused by splaying-out of the lower part). The reproductive orifice is further forward than in our other species, being a little in front of the slit of the respiratory orifice. Body and mantle some shade of grey, becoming paler towards the foot and with a dark lateral band on each side. The mantle bands form a lyre-shaped figure, and the right band arches over the respiratory orifice without sending a branch below it. The bands are set at a higher level than in A . hortensis. The tubercles of the mid-dorsal line are larger and paler than those on each side, forming a keel (hence the sectional name Carinarion Hesse, applied to this species) : this is often more distinct in the young. The foot fringe is somewhat lineolated, especially towards the tail. External variation Var. grisea Collinge (i8Q2c), light silver-grey with dark bands; var. flavescens Collinge (1892^) (= var. circumscripta 0kland, 1923), light brownish-yellow, with dark bands and a yellow zone over the foot. Lohmander (1937) discusses whether these and other named forms are varieties or subspecies. Pallial organs As in A . ater. Retractor muscles The genital retractor is mainly inserted into the duct of the spermatheca, but usually sends a small branch into the middle of the free oviduct. Otherwise as in A. ater. Nervous system As in A . ater. Jaw Of the usual arcuate shape, crossed by ten to twelve ribs ; about 1-25 mm across, coloured yellow to pale brown. Radula Closely resembles that of A. hortensis, but the marginals often have the small ectocone better developed. Length 3-4 mm, formula .11.23 X 120. Alimentary system As in A . ater, except that the visceral mass is less twisted. Reproductive system (Text-fig. 4 i) The ovotestis is darkly pigmented, the hermaphrodite duct has the usual " claw " or seminal vesicle at its entry into the albumen gland, and the sperm-oviduct is pinkish in colour, with a broad yellow prostatic ribbon. The free oviduct is rather BRITISH SLUGS 129 long and slender, agreeing with that of A . intermedium in not being dilated terminally to contain a ligula as in A . hortensis. The spermatheca has a short stout duct and an elongated sac, wide at the base and tapering apically. It varies a good deal, sometimes assuming bizarre shapes. The vas deferens is about the same length as the epiphallus, which terminates with a slightly marked annular swelling. The upper atrium is very small, and contains no ligula. The lower atrium is long, dorso- ventrally flattened, and yellow. Spermatophore (Text-fig. 4 G) A chitinous tube about 4 mm long, with five low ridges of which the most prominent is finely toothed. Within the spermatheca, the Spermatophore is bent into a U, and is swollen for a short distance behind the slender coiled anterior end. On this swollen part, Lohmander (1937) describes, but does not figure, a small projection which anchors the Spermatophore to the mucous membrane of the spermatheca. 0kland (1923) figures an incomplete Spermatophore, and Lohmander (1937) complete ones. Mating Coitus lasts about twenty minutes. In contrast to A. hortensis, A. subfuscus and A . ater, there is little or no eversion of the genitalia. Development The ellipsoidal eggs, 3x2 mm, are yellow or sometimes dark amber, more flexible and translucent than those of other species of A rion. They are laid in clutches of up to thirty, from May to the autumn, and hatch in four or five weeks (or longer in cold weather). The newly-hatched young are 5 mm long, pale yellowish-grey ; not darker dorsally, but with a pale central line of larger tubercles forming a keel towards the tail. The lyre-shaped figure formed by the mantle bands is faint in front and darker posteriorly. Ecology A . fasciatus is common amongst dead leaves and moss and under logs and stones, in thickets, fields and waste places, and sometimes in gardens. Distribution (Map 6) Probably every vice-county of the British Isles, and in Iceland (? introduced), the Faroes, Scandinavia, France, northern Italy, Rumania, western Russia, ? Spain. Introduced into North America. Material examined Living from many places in Britain. Spirit material from Britain, France and Italy. 130 BRITISH SLUGS Arion hortensis Ferussac, 1819 Arion hortensis Ferussac, 1819: 65, pi. 2, figs. 4-6. Presumably France. Arion elongatus Collinge, 1894 : 66, pi. 5A, figs. 1-4. Arion coeruleus Collinge, 18976 : 444. First British record By Gray (1821 : 239). Diagnostic features Differs from A . fasciatus in the following : body semicircular in transverse section when contracted, no enlarged mid-dorsal tubercles, reproductive orifice further back, mantle band surrounds respiratory orifice, sole yellow or orange ; spermatheca globular, free oviduct longer and proximally more slender, spermatophore hooked posteriorly and either discoidal or pointed anteriorly, brown patch on buccal bulb. External appearance (PL i, fig. 4) Length extended 2-5-3 cm - When contracted, the body is semicircular, not bell- shaped, in transverse section. The reproductive orifice is below the posterior lip of the respiratory orifice. The dark brown or black back is sprinkled with yellowish- brown dots, giving a pepper-and-salt appearance, the sole is pale yellow to bright orange, and the mucus is yellow. In alcohol, the back becomes bluish-grey and the sole loses its orange colour. The lateral bands are placed lower on the body than in A. fasciatus, and run along the edges of the mantle, surrounding the respiratory orifice instead of arching over it. External variation Var. grisea Moquin-Tandon (1855), P a ^ e g re Y an d bandless ; var. nigra Moquin- Tandon, bands nearly obliterated by general dark pigmentation ; var. rufescens Moquin-Tandon, reddish with black bands ; var. caerulea Collinge (1892^), bluish with dark bands, and yellow sides. Pallial organs As in A . ater. Retractor muscles As in A . fasciatus. Nervous system As in A . ater. Jaw (Text-fig. 7 G) About i mm across, doubtfully distinct from that of A. fasciatus. BRITISH SLUGS 131 Radula Similar to that of A. fasciatus, but the ectocone of the marginal teeth is less frequently present. Formula .11.24 x IO - Alimentary system (Text-fig. 4 A) Visceral mass less twisted than in A. ater. The buccal bulb has a brown shield- shaped mark on the upper surface an apparently good specific character not recorded in the literature. Reproductive system (Text-figs. 4 B and c) The very darkly pigmented ovotestis lies over the apex of the stomach, near the posterior end of the visceral mass, and is largely exposed on the surface. The middle dilated portion of the hermaphrodite duct is much folded, yellowish- white, and the terminal slender part shows the usual " claw " or seminal vesicle where it enters the elongated albumen gland. The sperm-oviduct is pale pinkish-brown, with a conspicuous yellow ribbon-like prostate. The free oviduct is unusually long and slender proximally, and dilated distally before entering the small white upper atrium. The vas deferens is short, and the epiphallus about the same length. The spermatheca duct is short and stout, with a bulbous base, and the sac is spherical. The lower atrium is yellow, with a soft glandular covering. As in A. fasciatus and A. intermedius, there is no ligula in the upper atrium. However, within the dilated distal end of the oviduct (Text-fig. 4 c), two conspicuous longitudinal folds correspond functionally with this structure during coitus (Quick, 1946). Below the termination of the spermatheca duct is a region of thickened mucous membrane in the atrium. In the slugs observed in Swansea (see below), the entering spermatophore adhered to this region. The epiphallus terminates in a short papillate papilla, which is very conspicuous when the atria are everted in coitus (Text-fig. 4 E). Both British and Dutch slugs show some variation in the folds of the oviduct representing the ligula, and in the relative length and thickness of the firm carti- laginous part ; but these differences could be due to differences in the degree of maturity of the animals, and to the extent of contraction during fixation in alcohol. Spermatophore (Text-figs. 4 F and M) Two types of spermatophore have been found in slugs from different localities. Since the spermatophores of Arion are seldom seen, it seems better to regard the slugs bearing the two types as varieties or local races, rather than as distinct species, until further anatomical or ecological differences are demonstrated. Slugs from Reading and from Zaandam in Holland (collected by Mr. D. Aten) have spermatophores in the form of simple chitinous tubes, 6-5 mm long, recurved at the slender posterior end and slightly shouldered near the anterior end, smooth and without denticulation (Text-fig. 4 F). Slugs from a garden in Eaton Crescent, Swansea (Glamorgan), which otherwise agree with those from Reading, have the very different spermatophores described 132 BRITISH SLUGS by Quick (1946). These are 5 mm long, shaped like cloves, with the anterior end forming a flattened disc with a crenulated edge, and with a ridge carrying about fifty-six forwardly pointing denticulations running the whole length of the convex side (Text-fig. 4 M). Mating (Text-fig. 4 D) Mating occurs in April and December, and probably in other months. After the usual " following" and licking of mucus, slugs from Swansea (spermatophores as in Text-fig. 4 M) curve in a semicircle head to head, and the atria are everted as a translucent mass with the lower atria stretched to a narrow yellow ring and the lower atria in contact. A long slender mobile club-shaped process is everted, which plays over the partner's body in the same manner as the sarcobelum of Agriolimax. However, subsequent dissection shows it to be the everted slender proximal part of the oviduct, functioning as a stimulatory organ, a modification which appears to be unique (Text-fig. 4 E). Coitus in Swansea slugs lasts for about an hour and a half. Gerhardt (1935) describes the mating of A. hortensis as lasting only twenty-five minutes, and the everted masses as small and featureless, in slugs whose spermatophores lacked serrations. This suggests that more than one species may be involved, though Mr. D. Aten (in litt.) states that the Zaandam slugs, having smooth spermatophores, evert their oviducts in coitus. Development The opaque yellow, sticky eggs measure 2-5 X 2 mm, and are laid in clusters of up to thirty. A second and third clutch may follow at three-weekly intervals. In the winter, the eggs take six or seven weeks to hatch. The newly hatched young are 4 or 5 mm long, and differ from those of A . fasciatus in having a darker dorsum and central mantle area. The usual body bands and lyriform mantle bands are present, and there is no dorsal line of pale conspicuous tubercles. The tentacles are violet-brown. Ecology This species is very common in gardens, allotments and fields, and burrows in the ground more than the other species of Avion. It can become a serious pest, by eating carrot, potato, etc. It is also frequent in woodland under logs and debris. Distribution (Map 7) Every county in the British Isles ; Scandinavia and western Europe to western Russia, (North Africa). Introduced into North America. Material examined Living and in spirit from many places in England and Wales, and from Zaandam, Holland. BRITISH SLUGS 133 Arion subfuscus (Draparnaud, 1805) Limax subfuscus Draparnaud, 1805 : 125, pi. 9, fig. 8. France. Arion fuscatus F6russac, 1819 : 65, pi. 2, fig. 7. First British record Possibly by Johnston (1838), as Arion subflavus (a nomen nudum). Up to about 1880, however, A. subfuscus was generally considered as a variety of A. ater. Diagnostic features Adults larger (6-7 cm) than A.fasciatus and A . hortensis, smaller than A . lusitanicus and A . ater ; differ from young of large species in smaller tubercles, narrower foot fringe, inability to contract to hemispherical shape. Internally differs from A . hortensis in relatively shorter proximal, slender, part of free oviduct, longer spermatheca duct. External appearance (PI. i, fig. 2) Length extended, from 5 to 7 cm. The colour is usually yellowish-brown, darker on the dorsum and head and on the body bands. On the mantle the right band completely surrounds the respiratory orifice. The foot fringe is yellowish and lineo- lated more or less distinctly with black, and the sole is pale yellow, sprinkled with whitish specks, and obscurely tripartite. The mucus, especially on the mantle, is yellow or orange. When contracted, A . subfuscus neither assumes the hemispherical shape nor exhibits the rolling reflex (p. 145) of A. ater. External variation This as usual depends on the relative development of black, red and yellow pigment, and the distinctness of the bands : var. rufofusca Draparnaud (1805), rufous with black bands ; var. bicolor Moquin-Tandon (1855), red with darker dorsum and no bands, foot fringe orange ; var . fuliginea Morelet (1845), dark brown, fringe yellowish; var. nigricans Pollonera (18876) , black ; var. cinereofusca Draparnaud (1805), ashy grey ; var. succinea Bouillet (1835), yellow or orange ; var. pegorarii Lessona & Pollonera (1882), quadrifasciate ; var. alba Esmark (1883), whitish. In most cases, the yellow pigment is largely contained in the mucus, and when this is removed the animal becomes brown or grey, as do alcohol specimens. Pallial organs, retractor muscles, nervous system As in A . ater. Jaw Brown, arcuate, about 1-5 mm across, with from ten to sixteen transverse ribs. 134 BRITISH SLUGS Radula (Text-fig. 3 H) About 4-5 X 2 mm. About ten more teeth on each side of each row than in A. hortensis. Formula .15.30 x 140. Alimentary system Similar to that of the other species of Avion, except that the visceral mass is rather more twisted than in A . intermedium and A . fasciatus, and less so than in A. ater. Reproductive system (Text-figs. 6 D and F) From the pale brown ovotestis, the greatly convoluted white hermaphrodite duct enters the albumen gland, with the usual "claw" or seminal vesicle. The common duct is voluminous and folded, the male or prostatic portion yellow and the female part pinkish-grey. The first part of the free oviduct is short and slender, and the longer distal part dilated. This part contains two prominent longitudinal folds of mucous membrane forming the ligula as in A. hortensis. The spermatheca duct is bulbous at its origin, then longer and more slender than in A. hortensis, and ends in a larger spherical spermatheca sac. The vas deferens and epiphallus are very similar to those of A. hortensis, but the terminal annular thickening is more pronounced. The upper atrium is small, the yellow glandular lower atrium of medium size with a wrinkled mucous membrane. Spermatophore (Text-fig. 6 G) Very different from that of A . hortensis : about 20 mm Ipng, slender anteriorly, then dilating, to taper again to an almost filamentous tail. The convex edge is finely denticulate. Mating Mating occurs in March, April and May, and perhaps other months. One of a pair follows the other for about half an hour, " licking " the caudal mucus. Then they curve around in a semicircle with the right side of the necks in contact. In about fifteen minutes the lower atria are everted as small yellow eminences. These rapidly enlarge as eversion is completed, and the combined atria form an ovoid bluish-white mass between the two animals, the junction of the two atria being barely visible as a fine line. After three-quarters of an hour the mass shrinks and the animals separate, and the spermatophores are momentarily visible, partly protruding from the spermatheca ducts as the remainder of the shrinking mass is withdrawn. For further details see Quick (1946). The slender portion of the free oviduct is not everted as a stimulator as it is in A. hortensis, where this portion of the oviduct is longer. The combined mass resembles that of A. ater, since the differing situation of the ligula does not affect the aspect. BRITISH SLUGS 135 Development The opaque leathery eggs, measuring from 2-25 X 2-25 to 3-25 X 2-25 mm, vary considerably in size and shape, even in the same cluster. Eggs are laid three weeks after mating. They are laid in masses of up to fifty, and tend to adhere together, several eggs sometimes being enclosed in a common tubular coat of mucus. They are white at first and become yellow or brown. Hatching occurs in from three to five weeks. The newly hatched young are about 6 mm long, grey, with darker dorsal region, and with lateral body and mantle bands. The tentacles are violet. Newly hatched A . ater are orange, straw colour or pale greenish-grey, and the tentacles dark grey rather than violet ; but the most notable difference is that the anterior ends of the mantle bands are closer together than in A. subfuscus (PI. i, figs. 9 and ii). Ecology A. subfuscus lives under logs and litter in deciduous and coniferous woods, and is one of the few species found in pine woods. It is also frequent in damp hedgerows, waste ground and some gardens. It feeds on the algal and fungal film on logs, and also on the larger fungi. In captivity it readily eats carrot, lettuce, oatmeal and dead slugs (Map 8). Distribution The whole of Great Britain and Ireland, except possibly parts of East Anglia and eastern Scotland. Most of Europe, north of a line through Orenburg and Odessa (Russia), northern Italy, Barcelona and Oporto. Introduced into North America. Material examined Living from many places in Britain. Spirit material from Britain, France, Luxem- bourg, Germany, Italy and Madeira. Arion lusitanicus Mabille, 1868 Avion lusitanicus Mabille, 1868 : 134. La Sierra d'Arriba, near Lisbon. Notes The name lusitanicus is applied to this species with some hesitation, since Mabille (1868) described the tubercles as " peu allonges ". However, Pollonera's description and figures (1889 : 626, pi. 9) leave little doubt about the identification. A. nobrei Pollonera (1889) is similar to A. lusitanicus but smaller, with smaller tubercles, completely black, and with the distal genital ducts even more strongly pigmented. A specimen from Portugal in the B.M. (N.H.) collections, identified as A. nobrei, agrees with this description. Cain & Williamson (1958) discuss specimens of Arion collected at Nuneaton, Warwickshire, which perhaps suggest that the status of A. lusitanicus in Britain may require further investigation. ZOOL. 6, 3. 10 136 BRITISH SLUGS First British record By Collinge (1893). Though again recorded by Collinge (1897^), the species was overlooked by Taylor (1902-07) and by other authors on the British fauna (e.g. Roebuck, 1921 ; Kennard & Woodward, 1926 ; Ellis, 1926 and 1951 ; Quick, 1949), until its rediscovery in Durham by Mrs. Vincent (Quick, 1952). Diagnostic features Large, up to 10 cm in length, with coarse tubercles like A . ater ; from which it is internally distinguished by the dilated distal part of the free oviduct, which lodges the ligula. Distinguished from A . subfuscus by coarse tubercles and a longer sperma- theca duct. External appearance The length when crawling is from 7 to 10 cm. The colour varies as in A. ater, and may be dark grey, reddish-yellow, brown or dull greenish-grey, with darker head and tentacles. The transversely lineated foot fringe is sometimes darker and sometimes lighter than the body, and the sole is generally pale, but dark in some Nuneaton specimens. The respiratory orifice does not dilate to the same extreme degree as in A. ater. In the younger stages there is on each side a dark lateral band (Text-fig. 5 D). On the mantle the bands form a lyre-shaped figure, the right band surrounding the pulmonary orifice on all sides, and anteriorly they are a little closer together than in A. subfuscus of similar size. Sometimes the bands are retained up to maturity. External variation Var. rufescens Collinge (1893), body dark red, sides of body bandless ; var. nigres- cens Collinge, black or plumbaceous ; var. olivaceus Collinge, various shades of olive-green ; var. flavogriseus Collinge, yellowish-grey, foot fringe lighter than the body. Pallial organs, retractor muscles, nervous system As in A . ater. Jaw Intermediate in size (3 mm across) between those of A . subfuscus and A . ater ; arcuate, crossed by from nine to thirteen rather broad even ribs ; pale brown or yellow in light examples, nearly black in dark ones. i Radula (Text-fig. 3 G) Intermediate in size between those of A. subfuscus and A. ater. The formula varies (in adult specimens from Durham) between C.I7.35 and C.I9.45. Alimentary system As in A. ater. BRITISH SLUGS 137 Reproductive system (Text-figs. 5 A and E) The very dark ovotestis lies a little further forward than in A. ater. The dilated central part of the hermaphrodite duct is folded in a zig-zag manner, and then narrows to form the usual " claw " at the albumen gland, which varies in size with the maturity of the animal. A yellowish-pink fold or ruffle accompanies the first part of the sperm-oviduct. The free oviduct is slender at first, and then becomes greatly enlarged, to narrow again slightly where it enters the upper atrium. This dilated part, in both the Durham and the Nuneaton examples, is deeply pigmented in a characteristic way (Text-fig. 5 A). The spermatheca duct is rather longer than in A. subfuscus, somewhat dilated at the origin. It also sometimes shows a slight dilatation, with stronger mucous folds, between the origin and the spherical sperma- theca sac. The vas deferens is about as long as the epiphallus, and the latter shows a conspicuous annular ring at its termination. The distal half of the epiphallus is deeply pigmented like the oviduct, the pigment usually tailing off in two tongues. In some individuals this pigmentation is less pronounced. The upper atrium is small, the lower pear-shaped with thick glandular-looking walls, sometimes yellow, and sometimes sprinkled with minute spherical white granules. The upper atrium contains no ligula, but the distal dilated part of the oviduct contains two conspicuous folds which apparently represent this structure, and function similarly (Text-fig. 5 E). In A. ater the ligula occupies the large upper atrium in both young and adult animals. Examination of the genital ducts of imma- ture animals of A. subfuscus and A. lusitanicus (Text-figs. 6 c and D) shows that the ligula lies in the oviduct, as in the adult, and does not " migrate " upwards or downwards. It is noteworthy that in young A. ater the oviducal branch of the genital retractor is inserted as in A. hortensis, A. subfuscus and A. lusitanicus ; while in adult A . ater (Text-fig. 6 K) the distal part of the oviduct becomes relatively much shorter, bringing the retractor close to the atrium. It could be argued that the lateral atrial pouch of A. ater is homologous with the dilated terminal portion of the oviduct of the other species, or alternatively that this portion of the oviduct is a diverticulum of the atrium. Seeing that this portion is so well devleoped in the early stages of growth, the second alternative is unlikely. There is in Geomalacus maculosus a long backward extension of the atrium ; but this carries back the epiphallus and the spermatheca, and does not affect the oviduct. Spermatophore (Text-figs. 6 H and i) A chitinous tube 20 mm long, armed with a spiral row of serrations, most prominent towards the anterior end ; and two low smooth ridges at the posterior end, which die out anteriorly. Mating (Text-fig. 6 E) The figure shows the appearance of the reproductive organs just before they are withdrawn after mating, with the partner's spermatophore protruding from the spermatheca duct. Observations on the mating of A. lusitanicus are too few and incomplete to permit of comparison with the other species. 138 BRITISH SLUGS Development The white eggs measure about 3 X 3-25 mm, but vary considerably in size and shape, both within and between clusters, and become yellower with age. In the laboratory, they have been laid in January and in March ; and in September by laboratory-bred animals only five or six months old. The clusters contain up to about fifty eggs, bound together by mucus, which hatch in about three weeks in the laboratory. Ecology In captivity, like most other slugs, A. lusitanicus is readily reared on lettuce, cabbage, oatmeal, etc.; but little is known of its habits in the wild. Distribution (Map 9) In the British Isles, known only from Berehaven, Bantry Bay, Ireland (Collinge, 1893) ; the garden of No. 24, North Bailey Road, Durham and the river bank adjoining (Quick, 1952) ; and the site of bombed cottages at Attleborough, Nuneaton, Warwickshire (Cain & Williamson, 1958). On the Continent, known from near Lisbon, Portugal ; Mentone and Pyrenees Orientales, France ; and Basle, Switzer- land. The species may be indigenous to Ireland and but recently introduced to Durham and Nuneaton, though it seems firmly established there. Probably it is more widely distributed in Britain, but has not been distinguished from A. ater. Material examined Living specimens from Durham and Nuneaton. Spirit specimens from Basle, Switzerland, and the Pyrenees Orientales. An immature specimen from Bantry Bay (Collinge Collection, Museum of Zoology, Cambridge) probably belongs to this species. Arion ater ater (Linnaeus, 1758) Limax ater Linnaeus, 1758 : 652. Sweden. Arion empiricorum Ferussac, 1819 : 60, pis. 1-3 (in part). First British record By Lister (1674). Diagnostic features Large size, coarse tubercles, wide foot fringe, large respiratory orifice ; short free oviduct surrounded by genital retractor muscle, ligula in upper atrium. Adults not certainly distinguishable in outward appearance from A. a. rufus, but usually black or dark brown with a grey sole, and rarely with a brightly-coloured foot fringe. Lateral pouch and ligula much smaller than in A . a. rufus, and vas deferens usually shorter. Upper atrium shorter than lower atrium. BRITISH SLUGS 139 External appearance (PL i, fig. 3) Length when fully extended generally about 14 cm, but may be even longer. The body tubercles are long and prominent, and darker than the furrows except in the young. The mantle is shagreened. There is no trace of a dorsal keel at any stage. The caudal mucus pore is conspicuous. The sole is more or less divided into median and lateral areas, the lateral areas usually the darker. The wide foot fringe is transversely lineolated, and in dark specimens the lines extend into the lateral areas of the sole. In pale individuals (except true albinos, which are rare) the head and tentacles are much darker than the rest of the body. The respiratory orifice is absolutely and relatively larger than in the previously described species. The very sticky body mucus may be colourless, or yellowish in red and yellow forms, that from the caudal pore always colourless. At rest, A. ater, like A. lusitanicus, but unlike A. subfuscus and the smaller species, can contract to a hemispherical shape, or even a larger portion of a sphere. External variation Since A. a. rufus has been generally considered as only a variety of A. ater, it is impossible at present to tell which of the very numerous named varieties belong properly to the latter. Probably most of the brighter varieties belong to A . a. rufus, and of the duller ones to A . a. ater. Extensive lists of varieties are given by Taylor (1902-07), Kennard & Woodward (1926) and Hesse (1926), of which the following is a short selection : var. ater Linnaeus (1758), black with grey sole ; var. aterrima Taylor (1905), completely black ; var. alba Linnaeus (1758), white ; var. albida Roebuck (1883), white with yellow fringe ; var. castanea Dumont & Mortillet (1856), brown with paler fringe ; var. albolateralis Roebuck (1883) (? = var. media Jensen, 1873), dorsum black, sides white ; var. reticulata Roebuck (1885), tubercles pale, furrows pigmented (i.e. the juvenile colouring retained by the adult) ; var. hiberna Mabille (1868), rusty purple with paler sides ; var. plumbea Roebuck (18840), leaden grey with yellow fringe ; var. succinea Miiller (1774), yellow with red or orange fringe ; var. coccinea Gistel (1848), vermilion ; var. marginella Schrank (1803), black with red fringe. Pallial organs Large vessels occupy the roof and floor of the pulmonary chamber. The kidney is curved into a rounded quadrangular form, surrounding the pericardium, and the ventricle lies posteriorly to the auricle. The anterior branch of the aorta curves round the anterior loop of the intestine, then runs forwards supplying branches to the anterior part of the body, passing between the visceral and pedal ganglia. The posterior aorta runs backwards and supplies the alimentary and genital systems, and passes between the visceral and pedal ganglia. The ureter and rectum terminate at the posterior lip of the respiratory orifice. 140 BRITISH SLUGS FIG. 4. Avion. A. A . hortensis internal organs in situ ( x 2) showing liver, exposed part of stomach, part of ovotestis, albumen gland, intestine,, aorta, crop, left salivary gland, nerve ring, characteristic pigmented area on buccal bulb. B. A. hortensis distal genital ducts ( x 4) with position of the partner's spermatophore indicated on upper atrium. G. A. hortensis distal portion of genital ducts (x 5-3) opened to show ligula in oviduct, glandular area below spermatheca, and papillate mucous membrane of epiphallus. D. A. hortensis mating pair (x 1-3) with slender parts of oviducts everted and functioning as stimulators. E. A. hortensis individual BRITISH SLUGS 141 B FIG. 5. Arion. A. A. lusitanicus reproductive organs (x 3). B. A. subfuscus distal genital ducts (x 3). G. A. ater ater distal genital ducts (x 3). D. A. lusitanicus- young individual ( x 10). Compare mantle bands with those of young A. subfuscus and A. ater (pi. i, figs. 9 & n). E. A. lusitanicus oviduct (x 5-3) opened to show position of ligula. immediately after coitus ( x 2) with everted genitalia, showing atria, everted oviduct, papillate epiphallus, partner's spermatophore adhering to base of spermatheca duct. F. A. hortensis spermatophore ( x 6-7). G. A.fasciatus spermatophore ( x 4), adapted from Lohmander. H. A. intermediusdistal genital ducts (x 4-7). I. A. fasciatus distal genital ducts (x 4). K. A. hortensis pallial region in ventral view, showing kidney, pericardium, auricle, ventricle, rectum and respiratory orifice. Muscles cut short. L. A . hortensis cephalic and buccal retractor muscles, ventral view. M. A. ? hortensis spermatophore (x 6-7) of a slug from a garden in Eaton Crescent, Swansea, Glamorgan. I 4 2 BRITISH SLUGS A. FIG. 6. BRITISH SLUGS 143 Retractor muscles The right and left cephalic retractors are widely separated at their origin, from the diaphragm behind the kidney. The pharyngeal retractor arises from the median dorsal body-wall. The genital retractor arises from the diaphragm immediately in front of the origin of the left cephalic retractor, ensheathes the short free oviduct, and sends a branch to the spermatheca duct. Nervous system (see Text-fig. 7 M) Highly concentrated in the adult, the commissures being short and the visceral ganglia closely united. Jaw Strong, arcuate, 3-5 mm across, crossed by a varying number of ribs (up to eighteen), variable in breadth, which denticulate the upper and lower edges. Colour yellow in pale specimens, nearly black in dark ones, the attached margin being darker than the free cutting edge. Radula (Text-fig. 3 F) 7-8 mm long by 3 mm wide. The number of lateral teeth varies from 20 to 25, and of marginals from 40 to 46 on each side, but the average formula is C.22 . 44 X 130. Alimentary system The short oesophagus leads through a large wide crop to the stomach, which forms the posterior part of the alimentary canal. The salivary glands on each side of the crop are large, flattened and much lobulated. The intestine, with one anterior loop, is twisted through about one and a half turns more than in the young of the smaller species. Reproductive system (Text-figs. 5 c and 6 L) The proximal parts resemble those of other species of A rion (see Text-fig. 5 A). FIG. 6. Avion. A. A. ater ater distal genital ducts (x 10) of a young individual, showing long atrium and position of ligula. B. A . ater ater genital organs ( x 3-3) of a nearly full-grown but immature individual, showing relative sizes of ovotestis, albumen gland, common duct and distal portions of ducts. C. A, lusitanicus genital organs ( x 6-7) of an immature individual, showing relative sizes of organs and position of ligula. D. A. subfuscus distal genital ducts (x 6-7) of a young individual, showing ligula in lower oviduct. E. A. lusitanicus slug after coitus, with atrium everted. The ligula, with the oviducal orifice in its lower anterior part, surrounds the orifices of epiphallus and spermatheca. The partner's spermatophore projects from the spermatheca duct. F. A . subfuscus distal genital ducts ( x 3-3). G. A. subfuscus spermatophore (x 3-3), and portions of spermatophore (x 16-7) from near anterior end, centre and posterior end. H. A. lusitanicus spermato- phore (x 3-5). I. A. lusitanicus portion of posterior end of spermatophore (x n). K. A. ater rufus distal genital ducts (x 3-3). L. A, ater ater distal genital ducts (x 3-3). 144 BRITISH SLUGS The short free oviduct, ensheathed by the genital retractor, enters the upper atrium apically. It is not dilated, and does not contain the two conspicuous folds of A. hortensis, A. subfuscus and A. lusitanicus. However, the upper atrium contains a somewhat similar folded mass, arising from the walls of the atrium and the termina- tion of the oviduct, known as the ligula. This is much smaller than in A. a. rufus, where it is contained in a lateral enlargement of the atrium. The spermatheca duct is relatively longer than in A. intermedium, A. fasciatus, A. hortensis and A. subfuscus, is not bulbous at the base, and receives a branch from the genital retractor. The vas deferens is usually less than one and a half times as long as the epiphallus, which terminates in a thickened ring at the atrium. Spermatophore (see Text-fig. 7 L) This rapidly disintegrates in the spermatheca, so that it can only be obtained intact soon after coitus. Two specimens were obtained in this way, which are 17 and 18 mm long. Each is somewhat dilated near the proximal end, and tapers in each direction. A finely serrated ridge runs nearly the whole length, the serrations pointing forwards. The epiphallus measures only n mm long in alcohol specimens ; so, unless it is much longer in life, part of the spermatophore must be formed during coitus. Mating Occurs in June and July, at any rate in Wales, after dark. After about half an hour of following and licking, the animals curve in a semicircle, neck to neck, and evert their atria to form a bluish- white mass. They separate after about half or three-quarters of an hour, when the spermatophores can be seen protruding from the spermatheca ducts, while the shrinking ligulae and atria are quickly withdrawn. Adams (1910), Gerhardt (1940) and Quick (1947) give fuller details. Development The eggs are variable in size, usually about 5x4 mm. They are opaque and leathery, pearly white when laid but turning brown. They are laid in clusters in the soil, two or three weeks after coitus. The first cluster may contain 150 eggs or more, and one or two subsequent clusters fewer than this. The eggs hatch in from four to six weeks. The young, 10 mm long, are pale straw colour or sometimes greenish, with darker head or tentacles. They are usually bandless, and if faint bands appear after a few days they quickly fade. Yellow pigment is concentrated in the tubercles. In the young of dark varieties the black pigmentation begins in the dorsal furrows and spreads downwards, producing a reticulate pattern which very occasionally persists in the adult ; though as a rule the pigment of pale adults is concentrated in the tubercles, leaving the furrows paler. The sole is the last part to pigment. Like the other species of Arion, A. ater shows in the later stages of embryonic development a cephalic and a caudal vesicle, which pulsate alternately. The tubular caudal vesicle persists to within a few days of hatching (Text-fig. 18 F). The jaw at hatching does not show any sign of bilateral origin like that of Agriolimax. BRITISH SLUGS 145 Behaviour Adults of A . ater exhibit a peculiar rolling reflex, if touched when fully (or almost fully) contracted. The body sways from side to side with a simultaneous screwing motion, with a periodicity of about two seconds. The movement cannot always be elicited, but may be quite violent. As far as is known, no other slugs show this reflex. It is tempting to explain it in terms of alternate contraction of the cephalic retractors, which have separated origins in Avion. However, the reflex is only doubtfully elicited from A . lusitanicus, and repeated attempts to elicit it from other British species of A rion have always failed. Ecology A. a. ater is practically omnivorous, eating decayed vegetable matter, dead mice and rabbits, and animal faeces. In the lowlands, it is common in grass fields, woods, hedgerows and waste ground, and on grassy downs and sea cliffs. It is often the only mollusc present on upland peaty moors and sphagnum bogs, where it is smaller than in the lowlands, and either black (often the var. aterrima) or very dark brown. Distribution (Map 10) The whole of the British Isles, northern and central Europe, Iceland and ? Russia. Probably some of the records from Spain, Portugal, Italy and the Mediterranean coasts and Atlantic isles refer to the related forms (A. a. rufus, A. lusitanicus and possibly others). Introduced into North America. Material examined Living specimens of A. a. ater, as distinct from A. a. rufus, have been identified from the following localities in the British Isles : Exeter, Littlehampton and Collompton in Devon ; Netley Heath, Surrey ; Howe Wood near Littlebury, Essex ; Reading, Berkshire ; Thorpe St. Andrews, Brundall Marshes and Wheatfen Broad in Norfolk ; Little Shelf ord, Homingsea and Durnford Fen in Cambridgeshire ; Cefn Bryn, Gower and Llangennith in Glamorgan ; Capel-y-ffin, Brecon ; Skokholm Island, Pembroke ; Abersoch, Caernarvon ; Bromborough, Cheshire ; Pentland Hills, Edinburgh ; Courtmacsherry, Cork. Arion ater rufus (Linnaeus, 1758) Limax rufus Linnaeus, 1758 : 65. ? Sweden. Arion empiricorum Ferussac, 1819 : 60 (in part). Arion sulcatus Morelet, 1845 : 28. Notes See Quick (1947). 0kland (1923) believes it to have been introduced to Sweden in historical times. Ferussac's empiricorum includes A. a. ater, A. a. rufus, and perhaps also A . lusitanicus and other species. Moquin-Tandon's description (1855-56, 2 : 10) of empiricorum, and his fig. i on pi. i, could serve for either A. a. ater or 146 BRITISH SLUGS A. a. rufus ; but his fig. 12 represents the genitalia of A. subfuscus, A. lusitanicus or a similar species. Cain & Williamson (1958) have studied pigmentation and genital anatomy in populations referable to A. a. ater and A. a. rufus. Their evidence suggests that only the former is indigenous to the British Isles, where A. a. rufus is an introduced alien associated with cultivated land. In Europe the natural ranges of the two forms seem not to overlap widely, since A. a. ater apparently occupies Scandinavia and A. a. rufus much of the rest of the continent, but it is not yet known how the two forms interact along their natural boundary. However, two populations near Oxford show the intermediacy of character combined with high variability which is to be expected from hybrids. This suggests that the two forms should be considered as geographical races. First British record By Gerhardt (1940), on specimens from Swansea, Glamorgan. The subspecies had been considered by previous British authors as merely a variety of A . a, ater. Diagnostic features Adult not certainly distinguishable from A. a. ater on external appearance, but usually yellow to reddish-brown, with a creamy yellow sole and bright orange or red foot fringe. Internally, upper atrium longer than lower, much larger ligula in lateral pouch, vas deferens usually longer than in A. a. ater. Young have mantle bands, rarely found in A . a. ater. External appearance, external variation, pallial organs, retractor muscles, nervous system, jaw, radula, alimentary system As in A . a. ater. Reproductive system (Text-fig. 6 K) As in A. a. ater, except for the distal genital ducts. The upper atrium is larger, and exhibits a lateral bulging that lodges a much larger ligula. The lower atrium is shorter than the upper. The vas deferens is relatively longer, usually more than one and a half times as long as the epiphallus and sometimes nearly twice as long. The oviduct, instead of entering the apex of the atrium formed by the lateral bulge, enters between this and the entrance of the epiphallus. Sometimes (as in specimens from Limeslade Bay, Swansea) the lateral bulge is narrower and prolonged further backwards. Occasional specimens of A . a. ater show a suggestion of a lateral bulge, but the size of the ligula, and the relative sizes of upper and lower atria and the vas deferens and epiphallus, serve to identify it. Spermatophore (Text-fig. 7 L) Probably longer than that of A. a. ater (about 25 mm long), and even more disproportionate to the size of the epiphallus in spirit material. This may be associ- ated with the longer period of coitus, if the spermatophore is formed during coitus. BRITISH SLUGS 147 Mating A . a. rufus attains maturity later in the year than A . a. ater, and mates in September and October, at any rate in South Wales. Mating resembles that of A. a. ater, except that coitus lasts for two hours. For further details, see Gerhardt (1940) and Quick (1947). Development The eggs are like those of A. a. ater. The newly-hatched young are pale yellow or orange, and differ from those of A. a. ater in having (at birth or after a few days) dark mantle and body bands, which persist for a few months. In individuals which will be dark when adult, the course of pigmentation is as in A. a. ater. The young can be distinguished from those of A . subfuscus by their coarser tubercles, and by the closer approximation anteriorly of their mantle bands (PI. i, figs. 9 and n). Behaviour A. a. rufus shows the same rolling reflex as A. a. ater. Ecology In Britain, A. a. rufus is more likely to be found in gardens and parks (though sometimes at a considerable distance from dwellings) than in wilder places. It never seems to occur in peaty moors or sphagnum bogs ; though this may reflect its introduction by man, and consequent restriction to cultivated land, rather than dependence on calcium in the soil. Distribution (Map n) Not fully known, since A. a. rufus has only recently been distinguished sub- specifically from A. ater. Authentically known in Britain from Glamorgan, Somerset, Berkshire, Oxford, Essex, Cambridge and Leicestershire. It seems to be the native form in Europe south of Denmark, though the natural ranges of the two subspecies are insufficiently known. Material examined Living specimens from Monkton Coombe near Bath, Somerset ; Chingford, Essex ; Basildon, Berks ; Coombe End, Oxford ; Lords Meadow near Cambridge ; and the Swansea district, Glamorgan. Spirit material from Loughborough, Leicester- shire ; Borgholm, Oland Island, Sweden ; Froedensborg, NE. Zealand, Denmark ; Canton Solothurn, Switzerland ; and from France, Corsica and Portugal. Superfamily ZONITACEA Family LIMACIDAE Slugs with a small calcareous shell almost always completely enclosed by the mantle. The dorsum is keeled posteriorly or right up to the mantle. There is no I 4 8 BRITISH SLUGS caudal mucus gland. The sole is tripartite and a supra-pedal groove is present (aulocopod). The jaw is smooth, usually with a median projection (oxygnath), and the lateral radular teeth are tri- or bicuspid, the marginal teeth aculeate. The spermatheca duct is short, generally arising from the atrium. FIG. 7. Limacidae. External appearance. A. Milax 'keel extending forward to mantle ; mantle granulate with horseshoe furrow ; respiratory orifice behind centre of mantle ; genital orifice between upper tentacle and respiratory orifice. B. Agriolimax keel extending only a little way forward ; tail truncate ; mantle con- centrically ridged with nucleus over respiratory orifice, behind centre of mantle ; genital orifice close behind upper tentacle. C. Limax keel extending a little way forward ; tail not truncate ; mantle concentrically ridged with nucleus in median dorsal line ; respiratory orifice behind centre of mantle ; genital orifice close behind upper tentacle. D. Milax chevroned foot-sole, stimulator protruded. E. Lehmannia marginata jaw. F. Agriolimax reticulatus jaw of very young individual, showing bilateral origin. G. Avion hortensis jaw, for comparison. H. Limax maximus shell. Avion ater rufus. I. Pair in copula. K. Portion of posterior end of sperma- tophore (x 24). L. Spermatophore (x 1-7). M. Ganglia and commissures of nerve ring (buccal ganglia omitted). BRITISH SLUGS 149 Subfamily PARMACELLINAE The shell is paucispiral, not completely enclosed by the mantle (in Parmacella], or flat and enclosed (in Milax). The mantle is granular, bearing a horseshoe-shaped groove, and the respiratory orifice lies behind the middle of the right margin. The genital orifice is between the respiratory orifice and right upper tentacles. The dorsum is keeled up to the mantle. The central and lateral radular teeth are tricuspid. The intestine has one forwardly directed loop, and the rectum lacks diverticula. An epiphallus secretes a spermatophore, and atrial glands are present. Milax is the only British genus. Watson (1930) considers that Parmacella and Milax arose from a common stock ; Parmacella, with its spiral shell, embedded pedal gland, and ocular retractor crossing the penis, being the more primitive. Genus MILAX Gray, 1855 Type species Limax gagates Draparnaud, 1801. The shell, completely enclosed by the mantle, has a median non-spiral nucleus near the posterior margin. The pedal mucus gland lies free in the body cavity, and not embedded in the foot below it, as in the other genera. The right ocular retractor lies to the left of both penis and vagina. In M. sowerbyi and M. gagates an atrial stimulator is present. The median area of the sole is crossed by A-shaped grooves. Milax is without lateral body bands at all stages of growth. Watson (1930) considers that, of the British species of Milax, M. gagates (with more lateral and fewer marginal radular teeth, and a wider distribution) is the most primitive, and M. budapestensis (with fewer lateral and more marginal teeth, and no stimulator) the most specialized. A common continental species, M. marginatus (Draparnaud, 1801) (= M. msticus Millet, 1843), which it seems possible may yet be discovered in Britain, is a yellowish slug with small black spots on the body and mantle and a dark band on each side of the latter, and resembles M. budapestensis in lacking the atrial stimulator. Milax gagates (Draparnaud, 1801) Limax gagates Draparnaud, 1801 : 100. Presumably near Montpellier, France. Amalia parryi Collinge, 1 89513 : 7. Amalia babori Collinge, iSgjc : 294. Notes Two species are currently confused under the name gagates. The common British species is distinguished by its smooth genital stimulator, and less certainly by its smoother appearance (with flattened tubercles) and paler sole. The second species is primarily Mediterranean in distribution, though there is one hitherto unpublished 150 BRITISH SLUGS British record (p. 156). It has two rows of large papillae on the stimulator, and also more prominent tubercles and a darker sole. It is not easy to determine the proper application of the name gagates. There are no slugs among Draparnaud's types at the Naturhistorisches Museum, Vienna (Locard, 1895 : 154; confirmed by Dr. O. E. Paget in litt.}. Both species occur at Marseilles, only eighty miles from Draparnaud's home at Montpellier. Drapar- naud's description does not deal with the internal anatomy. However, he describes gagates as " tres-lisse, tres-luisante " (1801) and " nitidus ; corpore striato subrugoso" (1805). This strongly suggests the north-western species, since he applies " sub- rugosus " to other slugs as smooth as this, and uses " rugosus " only for those as rough as the Mediterranean species. Few early authors described or figured the condition of the stimulator, from which alone their application of the name gagates could be determined. Lessona & Pollonera (1884 : 105, pi. 2, fig. 2) use this name for Italian slugs with papillate stimulators. Germain (1930, fig. 52 A), in treating the French fauna, gives a figure of a papillate stimulator which is apparently copied from Lessona & Pollonera, and does not mention the locality. Taylor (1902-07, fig. 159) shows the smooth stimulator of a British slug. The name parryi Collinge is a synonym of gagates, as the latter is here interpreted, since one of the type specimens from Santa Cruz, Teneriffe, shows on dissection a penis, epiphallus and stimulator like the British species. So does one of a series from Haleakala Maui, Hawaii, apparently the types of babori Collinge. The following names, among others, cannot at present be allocated to either of the species with any certainty : Limax maurus Quoy & Gaimard, 1824 : 4 2 7- Port Jackson, Sydney, Australia. Parmacella nigricans Schultz, 1836, 1 : 125. Palermo, Sicily. Amalia mediterranea Cockerell, 1891 : 331. Algeria. Amalia mediterranea forma similis Cockerell, 1891 : 332. Catania, Sicily. However, specimens that I received from Catania in 1947 proved to be the species with a papillate stimulator. First British record By Thompson (1840 : 205). Diagnostic features Uniform grey or black colour, with darker keel, respiratory orifice without pale margin, mucus colourless ; smooth genital stimulator, rather thick spermatophore, not hooked at the thick end and with spines distributed more evenly than in M. sowerbyi. Differs from M. cf . insularis in smooth, not papillate, stimulator ; and less certainly in smoother skin and paler sole. External appearance (PL i, fig. 12) Length extended about 5 cm. When contracted, the slug is more compressed laterally than M. sowerbyi. The colour is usually grey or black, getting lighter BRITISH SLUGS 151 towards the foot. The tubercles are flattened, making the slug rather smooth, and the intervening grooves are unpigmented. The keel is usually dark, and is abruptly angulated at the posterior end. The central area of the granulate mantle is delimited by a horseshoe-shaped groove, open posteriorly, with the arms angulated at the level of the respiratory orifice. The respiratory orifice is small and without a pale border, and is situated a little behind the centre of the right margin of the mantle. The sole is pale, distinctly tripartite, with the median zone crossed by A-shaped grooves (Text-fig. 7 D). Only this central area shows the locomotory waves. The mucus is sticky and colourless. External variation Var. plumbea Moquin-Tandon (1855), paler or darker grey ; var. rava Williams (1888), drab coloured, slightly fuscous, mantle paler; var. bicolor Taylor (1904), deep red on the sides ; var. benoiti Lessona & Pollonera (1882), black, keel whitish. Other varieties with a Mediterranean distribution mentioned by Taylor (1902-07 : 143-146) probably refer to M. cf. insularis. Shell (Text-fig. 8 K) Measures about 4 X 2-5 mm. White and shining. Somewhat saddle-shaped above, and flattened below. The nucleus is near the posterior margin, in the middle line, and the lines of growth are distinct. Viewed laterally, the shell is concave from back to front, with the nucleus at the highest point, and shows a groove separat- ing the upper part of the shell from the lower. Pallial organs The kidney has an extension to the right toward the rectum, and the auricle and ventricle lie anterior to the left half of the kidney. The rectum crosses over the common origin of the tentacular and pharyngeal muscles to the posterior lip of the respiratory orifice. Pedal gland Lies free in the body cavity, occupying half the body length. Its duct projects posteriorly from the glandular tissue for about 0-25 mm. Retractor muscles The pharyngeal and tentacular retractors are not separated, as in Arion, but have a common origin from the posterior edge of the diaphragm in the middle line. At the posterior border of the kidney this divides into the pharyngeal retractor, which is bifurcate for about one-third of its length, and the tentacular retractor. The latter soon divides into right and left branches, and these divide again much further forward into branches to the upper and lower tentacles. The penial retractor arises further forward, on the left side of the diaphragm. ZOOL. 6, 3. II 152 BRITISH SLUGS FIG. 8. Milax. Distal genital ducts ( X 4). A. M. gagates atrium opened to show stimulator. B. M. sowerbyi atrium opened to show stimulator. C. M. buda- pestensis. D. M. cf. insularis. Spermatophore (x 6-7), spines (x 33). E. M. gagates one spine. F. M. sowerbyi two spines. G. M. budapestensis three spines. H. M. cf. insularis papillate stimulator. Shell (x 2-7), dorsal and lateral views. I. M. sowerbyi. K. M. gagates. L. M. budapestensis. BRITISH SLUGS 153 Nervous system The cerebral ganglia are connected by a short broad commissure. The cerebro- pleural and cerebro-pedal commissures are short, so that the nerve ring closely surrounds the oesophagus. The pleural, visceral and abdominal ganglia are closely approximated, as are also the visceral and pedal ganglia. The abdominal ganglion is almost completely fused with the left visceral. There is little if any variation in the nervous system between the species of Milax. Jaw Brown, oxygnathous, measuring 1-7 mm across. Radula (Text-fig. 9 A) The central tooth has a mesocone and well-developed ectocones. The laterals have well-marked endo- and ectocones, nearly equal in size. Most of the marginals lose the ectocones, but five or six of the innermost teeth retain them. Formula .17.27, with slight variation (see p. 157). Alimentary system The brown oesophagus leads to a long capacious crop, and the intestine (which exhibits marked spiral torsion) extends well behind the stomach, thus contrasting strongly with the condition in Arion. The rectum runs forwards above the common stem of the retractor muscles. Reproductive system (Text-fig. 8 A) The spiral ovotestis, mainly hidden by the upper lobes of the liver, gives off the pale hermaphrodite duct. This is much folded in its anterior wider part, and the terminal slender portion bears an oval seminal vesicle at its entry into the linguiform albumen gland. The common duct is long, voluminous and folded. The spermatheca is an oval sac, with a short duct arising from the oviduct 1-5 mm before its termina- tion. The prostate is a yellow ribbon-like organ on the common duct. At the beginning of the free oviduct it gives off the somewhat convoluted vas deferens, which enters the apex of the epiphallus. The epiphallus is widest apically and has a rounded eminence or blunt caecum below the apex, a feature that is not shared by M. sowerbyi or M . budapestensis. At the insertion of the retractor muscle, the epiphallus, without any external sign, passes into the penis, which narrows towards its termination in the atrium. Before its termination the penis shows two more or less distinct dilata- tions, the upper one containing the blunt perforate penial papilla with a small pigmented diverticulum. The mucous membrane of the epiphallus is thrown into transverse circular folds, and that of the penis into longitudinal folds. A lobulated gland that can be unravelled into long glistening white tubules opens into the atrium. The atrium lodges a fleshy conical stimulator attached by its larger end, with the tip often folded back. The stimulator is generally smooth but occasionally has two or three minute papillae near the tip. 154 BRITISH SLUGS B row FIG. 9. Representative radular teeth (x 330). A. M.gagates. B. M. sowerbyi. C. M. budapestensis. M. sowerbyi, an individual one day old. D. Representative radular teeth (x 1,000). E. Jaw (x 67). BRITISH SLUGS 155 Spermatophore (Text-fig. 8 E) A brown chitinous tube about 10 mm long, widest at the centre and narrowing at the anterior end. Except at two places on the concave side, it bears prominent spines throughout. The spines have four main branches, and fourteen or sixteen terminal points. Mating Observations are very scanty, but apparently the partners during coitus are in close contact, and little or nothing of the genitalia is visible. Though the stimulator is often found protuded in spirit specimens, it is not visible during coitus. Mating has been recorded in spring, summer and winter. Taylor describes the eggs as 2 X 1-5 mm, transparent and thin shelled. This, if correct, is much smaller than the eggs of M. sowerbyi and M. budapestensis. Ecology Though widely distributed in the British Isles, M. gagates seems to be commoner near the sea than inland, and especially common in the south-west. In parts of Devon it is abundant in root crops, and can be a pest. It inhabits cliffs, wild places and gardens. In captivity, like most other slugs, it eats carrot, potato and oatmeal. Distribution (Map 12) M. gagates probably occurs in all the vice-counties of England, Wales and Ireland, the south of Scotland, the Isle of Man and the Clyde Islands. In Europe, its distribu- tion is essentially north-western, though specimens from Marseilles have been examined. Other records from the Mediterranean area probably refer to a closely- related species, here distinguished as M. cf. insularis (p. 156). M. gagates has been introduced into South Australia, Hawaii, California, Canary Isles and Tristan d'Acunha. It is not yet clear whether other records of introduc- tions into America, Bermuda, Ascension Island, St. Helena, South Africa, Australia, Tasmania, New Zealand and Polynesia refer to M. gagates or to M . cf. insularis. Fossil record Pleistocene to Recent. Material examined Living specimens from Epsom, Surrey ; Southwell, Nottingham ; Porthcawl, Glamorgan ; Haverfordwest, Pembrokeshire ; St. Agnes, Stilly Isles ; and Majorca. Spirit specimens from Aberdeen, and from Marseilles, France ; Santa Cruz, Teneriffe ; Calbaden Canyon, Puenta Hills, Los Angeles, California ; Kensington suburb, Adelaide, South Australia (coll. B. C. Cotton) ; and Haleakala Maui, Hawaii. 156 BRITISH SLUGS Milax cf. insularis (Lessona & Pollonera, 1882) Amalia insularis Lessona & Pollonera, 1882 : 57 (see 1884 : 103). Sardinia and Sicily. Amalia ichnusae Lessona & Pollonera, 1882 : 60 (see 1884 : 106). Sardinia. Notes If the name gagates is to be reserved for the north-western species with the smooth stimulator (p. 149), the valid name for the present species remains to be determined. Several names whose application is uncertain (some of which are listed on p. 150) are available within the gagates complex. It will require a thorough study of the Mediterranean forms to clarify the biological and nomenclatural situation. First British record This is the first record to be published. Mr. Armitage collected specimens near Bexhill, Sussex, about 1948, and the differences between these and M. gagates were confirmed by Mr. Watson (in litt.). All other specimens examined, from various parts of Britain, have proved to be M. gagates. Diagnostic features Differs from M. gagates in having large papillae on the atrial stimulator. Also, the slug is usually larger, blacker and less smooth, with a darker sole. External appearance As M. gagates, except for the usually larger size, more prominent tubercles, and more intensely black coloration, with the sole not conspicuously paler. External variation It is not at present possible to assign named varieties to this poorly understood species. Shell, pallial organs, pedal gland, retractor muscles, nervous system As in M. gagates, as far as is known. Jaw As in M. gagates, though varying from pale brown to nearly black in the material examined. Radula The teeth closely resemble those of M. gagates in form and number. Formulae of radulae examined were: M. cf. insularis C. 18.28 (Catania, Sicily), .17.28 X 105 BRITISH SLUGS 157 and .19.27 (Malta), .20.30 x 102 (Marseilles) ; M. gagates .15.31 X 100 (Aberdeen), .16.27 (Porthcawl), .17.27 X 96 (California), .19.27 X 102 (Marseilles). Alimentary system As in M. gagates. Reproductive system (Text-fig. 8 D) Here the differences from M. gagates are obvious. The stimulator (Text-fig. 8 H), instead of being smooth or having at the most two or three minute papillae near the tip, has large papillae disposed in four longitudinal rows near the base, diminishing to two rows and becoming smaller towards the apex. Sometimes the papillae are mucronate, and in one specimen they were found to be partly retracted. The atrial glands extend further backwards than in M. gagates, in a tongue-like prolongation. The epiphallus does not possess the sub-apical bulge seen in M. gagates. The small internally-pigmented accessory penial papilla, instead of being enclosed in the penis sheath, bulges externally ; but it seems likely that this character varies with the physiological state of the animal, in both species. Whereas Mediterranean specimens examined had four rows of papillae towards the bases of their stimulators, Lessona & Pollonera (1884, pi. 2, figs, i and 2 ; 6 and 7) figure "gagates " and insularis with only two rows. They describe ichnusae as having a single row of papillae, though their figure shows the stimulator as smooth (1884 : 106 and pi. 2, fig. 4). Possibly there is more than one species with a papillate stimulator in the Mediterranean region. Mr. Aten of Zaandam, Holland, reports (in litt.} finding M. gagates and M. cf. insularis in the Pyrenees Orientales, and that the latter when young has only a single row of papillae. This suggests that M. ichnusae may be an immature form. Spermatophore, mating, development, behaviour, ecology Not known. Distribution In Britain, once recorded from Bexhill, Sussex. In Europe, found in the Mediter- ranean region. Occurs together with M. gagates near Marseilles. Fossil record Not distinguishable from M . gagates. Specimens examined Spirit specimens from Marseilles and Valence, Malta, Sicily and Majorca. 158 BRITISH SLUGS Milax sowerbyi (Ferussac, 1823) Limax sowerbyi Ferussac, 1823, 2 : 96, pi. 8. London. Limax carinatus Risso, 1826 : 56. Limax marginatus Jefferies, 1862 : 132. Amalia maculata Collinge, 18956 : 336, pi. 23, fig. 6. Amalia collingei Hesse, 1926 : 139. First British record By Ferussac (1823). Diagnostic features Differs from M . gagates in brown colour speckled with darker patches, pale keel and margin of respiratory orifice, grooves between tubercles pigmented, keel not abruptly truncated, animal less compressed laterally when contracted, mucus yellow and more tenacious. Differs from M. budapestensis in broader, uniformly pale sole. Internally characterized by short blunt atrial stimulator, long conical spermatheca, tapered spermatophore hooked at blunt end and bare of spines at narrow end. External appearance (PI. 2, fig. 23) Length when extended about 7 cm. When contracted the slug is rather less compressed laterally than M. gagates, and the keel is not abruptly truncated behind. The body is usually pale or dark brown with darker speckling, with the keel paler and the grooves between the tubercles pigmented. The mantle grooves are as in M. gagates, but the respiratory orifice is pale margined. The tripartite sole is pale, and the sticky mucus yellow. Variation Var. alba Taylor (1904), entirely white ; var. fuscocarinata Cockerell (i886c), keel the same colour as the back ; var. nigrescens Cockerell, black with orange keel ; var. oretea Lessona & Pollonera (1882), with median dark streak on mantle found in Devon and Glamorgan. Shell (Text-fig. 8 i) Larger, thicker and more evenly oval than that of M. gagates, measuring 5x3 mm. Pallial organs As in M. gagates. Pedal gland The duct does not project beyond the glandular tissue. Retractor muscles The pharyngeal retractor is more deeply cleft than in M. gagates, and the two tentacular retractors separate sooner. The penial retractor arises nearer to the BRITISH SLUGS 159 common stem of the other muscles, and there is a pair of short muscles from the penis to the body-wall. Nervous system As in M. gagates. Jaw As in M. gagates, but a little broader from upper to lower margin. Radula (Text-fig. 9 B) As in M . gagates, except that there are a few more transverse rows of teeth, and there are fewer laterals and more marginals in each row, with two or three of the innermost or transitional marginals often retaining a minute ectocone. Formula 0.13.36 x 115. Alimentary system As in M. gagates. Reproductive system (Text-fig. 8 B) The lower genital ducts differ from those of M. gagates in several features. The short wide spermatheca duct arises from the free oviduct even nearer the atrium, and the sac has a narrowing backward prolongation. The epiphallus widens instead of narrowing towards its termination, and does not present the sub-apical lateral bulge of M. gagates, nor the small pigmented diverticulum at the distal end of the penis. The atrium contains a short blunt smooth stimulator. Spermatophore (Text-fig. 8 F) Thicker than in M. gagates, measures about 13 mm long. The thinner anterior end is smooth, and the curved posterior end bears recurved spines of three types. As usually found in the spermatheca, and figured by Taylor (1902-07, fig. 174) and others, the smooth anterior end terminates abruptly. However, if the spermatophore is taken very shortly after coitus, before the spermathecal fluid has had time to act upon it, the anterior end is found to be capped by a curious conical structure about 2 mm long, with a rounded apex, and formed by four leaflets with fringed edges (Quick, 1950). A fresh spermatophore of M. budapestensis does not have this cap, but no opportunity has occurred of examining a fresh spermatophore from M. gagates. Occasionally two spermatophores are found in the spermatheca in M. sowerbyi, but whether they are transferred during a single coitus (which is very prolonged) or on two separate occasions is not known. Mating After following and then curving around, the pair remain in close contact for twelve to eighteen hours, and little or nothing is visible of the genitalia. Pairing has been observed in October and November, but perhaps occurs at other times. 160 BRITISH SLUGS Development The eggs are 4x3-5 mm, soft, translucent and pale amber, laid in clusters of about a dozen, hatching in from four to six weeks. The embryo before hatching has a large flattened caudal vesicle nearly circular in outline. When hatched the young are 8 mm long, with a conspicuous pale keel. The mantle is speckled with black and sometimes has a dark median streak, which is retained in var. oretea when adult. Ecology M. sowerbyi is found in gardens, cultivated fields and rubbish heaps. It burrows in the ground, and can do considerable damage to carrot and potato crops. Distribution (Map 13) Occurs in probably every vice-county of England, Wales, Ireland and the southern half of Scotland, and in France, Belgium and Spain. Probably known under other names from Portugal, Italy, Greece and the north coast of Africa. Introduced into South America and New Zealand? Fossil record Pleistocene to Recent. Material examined Living specimens from many places in Glamorgan, Pembroke, Surrey, Berkshire and Sussex. Spirit material from Britain and Marseilles. Milax budapestensis (Hazay, 1881) Limax gracilis Leydig, 1876 : 276, nee Limax gracilis Rafinesque-Schmaltz, i82oa. Amalia budapestensis Hazay, 1881 : 40. Budapest. First British record By Phillips & Watson (1930). Diagnostic features Sole with dark central and paler lateral areas ; body when contracted tends to lie in a curve and is less compact and humped than M. gagates and M. sowerbyi. No atrial stimulator, spermatophore slender and spirally twisted. Radula has more marginal teeth, and spermathecal duct is longer, than in M. gagates and M. sowerbyi. External appearance (PI. 2, fig. 20) The smallest British species of Milax, very slender when extended to 5 cm. The dorsum is dark, sometimes nearly black or with a brownish tinge, with a dirty BRITISH SLUGS 161 yellow or orange keel. The grooves between the dorsal and the lateral, somewhat polygonal, tubercles are deeply pigmented. The mantle is sometimes paler than the dorsum, the horseshoe-shaped groove deeply pigmented, and the small respiratory orifice has a grey margin. The peripodial groove and margin of the sole are deeply pigmented, the lateral areas of the sole grey, and the median area dark grey or nearly black. The mucus is viscid and colourless, but in the mantle area becomes yellowish after repeated irritation. External variation Variation is confined to the intensity of the general grey colour ; to the tint of the keel, which varies from yellow to brownish-orange ; and to the sole, whose lateral areas are occasionally darker than the central area. SMI (Text-fig. 8 L) Concave or flat below, measuring 3 x 1-25 mm, brownish in colour. Pallial organs As in M. gagates. Pedal gland The duct extends behind the glandular tissue for about 5 mm. Retractor muscles The tentacular and pharyngeal retractors are usually rather more deeply cleft than in M. gagates, less so than in M. sowerbyi. Nervous system As in M. gagates. Jaw Brown and oxygnathous as in the other species but smaller, measuring about 1-5 mm across and 0-5 mm in height. Radula Differs from those of the other species in having the basal plate of the central tooth relatively broader, the aculeate mesocones of the marginals more slender, fewer lateral teeth and more marginals. Formula .7-8.38-40. Alimentary system As in M. gagates. Reproductive system (Text-fig. 8 c) The pale spirally twisted ovotestis has five or six closely approximated lobes, 162 BRITISH SLUGS each composed of numerous follicles. The hermaphrodite duct is slender for the greater part of its length, but becomes dilated and folded near the albumen gland, and here shows a small seminal vesicle. The common duct with a broad yellow prostatic ribbon is folded S-wise, and after parting from the vas deferens contracts to form a relatively long slender free oviduct. At about two-thirds of its length, the wider relatively long spermatheca duct arises, leading to a cylindrical sac with a rounded apex. The rather long flexuous vas deferens enters the epiphallus sub- apically. In the writer's experience the epiphallus and penis are long and slender, but Phillips & Watson (1930) describe and figure a short blunt form in addition, and find this the commoner. It is not known if this is a true dimorphism, or only the result of the physiological condition. Hazay (1881, pi. i) shows an intermediate form of penis and epiphallus, and Simroth (1885, pi. 10, fig. 13) the long form. Both forms occur in Belgian specimens, sent to me by Dr. W. Adam. The atrium receives the slender ducts of a pair of lobulated atrial glands, and has no stimulator. Spermatophore (Text-fig. 8 G) Length about 16 mm, anterior end slender, posterior end spirally twisted. No trace of a frilled cap as in M. sowerbyi, even in sperm at ophores removed during or immediately after coitus. Except for the first 2 mm at the anterior end, the Spermato- phore is covered by forwardly-recurved branching spines, which are smaller and less branched towards the ends. There are two rows of spines anteriorly, three or four rows on the posterior two-thirds. Mating Occurs during November, December and January, under cover of loose stones or logs. Coitus generally starts in the evening and continues until the following mid-day or later. A little of the partly everted atria and the two penes is visible between the necks of the partners. The atrial glands are partly contained in the everted atria, together with the distal ends of the genital ducts. Development The ellipsoidal yellow leathery eggs are laid in small clusters underground, and measure 2-9 X 2-25 mm. Those laid in December hatch in March. The young at hatching are 4-5 mm long, pale yellowish-grey with a recognizable keel. Behaviour Whereas when at rest the other species of Milax assume a compressed helmet shape, M. budapestensis is usually found only half contracted, and curved into a semicircle. Ecology Occurs mostly in gardens and allotments, under stones and rubbish, and can do considerable damage to roots and tubers. Though much less common in wild places, there are records for such situations in Wales and Cheshire. BRITISH SLUGS 163 Distribution (Map 14) Recorded from many localities in the British Isles, mainly in western England and Wales, but also in south-eastern England, southern Ireland and the Hebrides. On the Continent, known from Belgium, Germany (Wurtemberg, Tubingen, the Rho'n Mountains and Wiirzburg), North Italy (Verona, Vicenza and Padua), Hungary (Budapest), Transylvania, Bulgaria and Crimea. It probably occurs in many places between these widely-separated localities, in the zone from the British Isles to the Crimea. For a map and further details, see Phillips & Watson (1930) and Ellis (1951). Fossil record Recent. Material examined Living specimens from Berkshire, Glamorgan, Pembroke and Denbighshire. Spirit material from Britain and Belgium. Subfamily LIMACINAE Limacidae in which the keel rarely extends forwards as far as the mantle. The nucleus of the enclosed shell is terminal and lies to the left of the mid-line. The mantle is concentrically ridged and lacks a horseshoe-shaped furrow. There is no well- developed epiphallus, no spermatophore and no atrial gland. The stimulatory organ, when present, is a penial sarcobelum, and not an atrial stimulator as in Milax. The endocones of the lateral radular teeth, when present, are more or less united with the mesocones. The intestine has one or two forwardly-directed loops. Genus AGRIOLIMAX Morch, 1865 Type species Limax agrestis Linnaeus, 1758. The right ocular retractor lies to the left of both penis and vagina. The intestine has one forwardly-directed loop, and the right lobe of the liver forms the apex of the visceral mass. A penial sarcobelum is present, more or less developed. The nucleus of the concentric mantle ridges lies to the right of the middle line, over the respiratory orifice. The tail is obliquely truncate. Pilsbry (1944, 1948) adopts the name Deroceras Rafinesque-Schmaltz (18200 : 10) for this genus, as do most American and many European authors. Watson (1943 : 54) discusses the question. Ellis (in press) has submitted to the International Commission on Zoological Nomenclature a proposal for the suppression of Deroceras and other older names, and the validation of Agriolimax. Hesse (1926) mentions sectional names for the first three species considered here. Agriolimax s.s. (including A. agrestis and A. reticulatus) has a rectal caecum and 164 BRITISH SLUGS a more or less tufted penial appendix, whereas Hydrolimax Malm (including A . laevis) lacks both caecum and appendix, but has a long tubular penial diverticulum. Other sectional names have been proposed for groups of extra-limital species, such as Krynickillus Kaleniczenco, which lacks caecum, appendix and sarcobelum. However, several species show combinations of characters not covered by existing sectional names. A. caruanae has a tufted penial appendix like Agriolimax s.s., but lacks a rectal caecum like Hydrolimax ; while one or both of its penial diverticula may correspond to the latter's single but minutely bifid diverticulum. A slug collected in Cyprus by A. R. Waterston (? A. cyprius Simroth, 1906, or A. panormitanus Lessona & Pollonera, 1882) has a tufted appendix and a single diverticulum. Of two Abyssinian slugs described by Quick (1954) , A . gughensis lacks caecum, appendix and diverticula but has a long, narrow, backwardly-directed sarcobelum ; while A, scotti lacks caecum, appendix and sarcobelum, but has two diverticula. In view of the intergradation and overlapping between species of which the anatomy is known, and of the number of species (especially in south-eastern Europe) of which it is not known, the use of sectional names within this genus does not seem useful. Agriolimax reticulatus (Miiller, 1774) Limax reticulatus Miiller, 1774 : 10. Denmark. Limax canariensis d'Orbigny, 1839 : 47. Krynickillus minutus Kalenickzenko, 1851 : 224. Notes The name agrestis has been used for this species by most British authors (see p. 170). First British record By Lister (1674 : 99) . Diagnostic features Distinguished from A. laevis and A. caruanae by larger size, opaque appearance with very variable coloration, white sticky mucus and less active movements ; and internally by the presence of a rectal caecum. Differs from A . agrestis in the trifid crenulate penial appendix, and the posterior situation of the ovotestis. External appearance (PI. 2, fig. 15) Length about 3-5 cm. The tail is obliquely truncated, the back keeled for a short distance at the hind end, and the sole tripartite. The respiratory orifice is at about two-thirds of the distance from front to back of the mantle, and the reproductive orifice close behind and below the right upper tentacle. The concentric striae of the mantle disappear in alcohol. The mucus is whitish on account of calcareous granules. BRITISH SLUGS 165 The colour is variable, with the body usually marked with brown or grey. The respiratory orifice has a conspicuous pale border. External variation The colour varies from pale cream to bluish-black, but is usually some shade of brownish-yellow, with darker grooves and scattered dark brown markings of varied shapes and sizes. Named varieties and subvarieties are very numerous. Many are practically synonymous, while some of those listed by Taylor (1902-07) refer to other species. Individuals often become darker as winter approaches. The following varieties may be recognized : var. cineracea Moquin-Tandon (1855), entirely ash coloured ; var. violacea Gassies (1849), lilac or slate-coloured ; var. rufescens Dumont & Mortillet (1856), rufous ; var. reticulata Miiller (1774), grooves dark, giving a reticulate appearance ; var. nigra Morelet (1845), black, with pigment sometimes invading the sole. Albino forms occur occasionally. Shell (Text-fig. 10 F) The right border is convex. Pallial organs (Text-fig. 10 A) When the mantle is reflected to the right, a lobe of the kidney is seen to cover the rectum, and the short retractor penis to arise from the diaphragm at the anterior border of the pericardium. Retractor muscles (Text-figs, n G and H) The cephalic retractor muscles arise as a single stem in the mid-line, a short distance behind the diaphragm. The main stem usually divides basally, to form the right ocular retractor, and a common stem for the left ocular and the buccal bulb retractors (Text-fig, u G), but variations occur (Text-fig, n H). The genital retractor arises from the diaphragm near the front of the kidney, and is inserted between the vas deferens and the constriction above the sarcobelum. Nervous system This is very similar to that of Milax. Jaw Pale golden, of the usual oxygnathous type. Radula (Text-figs, n L and o) As in all Agriolimax, the endocones of the lateral teeth are delicate, lying close to the mesocone and on a slightly more superficial plane. The basal plates of the central and lateral teeth are larger and relatively narrower than those of A. agrestis. Table I compares the radulae of the four British species of Agriolimax. 166 FIG. 10. Agriolimax. Dissection with mantle reflected to the right. A. A. reticu- latus (x 2), ovotestis extends much further backwards than in A. agrestis. B. A. agrestis (x 2), ovotestis does not extend much further back than the rectal caecum. C. A. caruanae (x 2-7), ovotestis far forwards, exposed on left side. No rectal caecum. D. A. laevis (x 2-7). A. caruanae. E. Pallial region and cephalic retractors (x 12). K. Mating pair with sarcobela protruded. Shell (x 4). F. A. reticulatus. G. A. agrestis. H. A. caruanae. I. A. laevis. BRITISH SLUGS 167 TABLE I. Radular Formulae of the British Species of Agriolimax Morch Locality Date Formula (mm) Remarks Capel-y-mn, Brecknock Blackpill, Swansea Mumbles Rd., Swansea Porteynon, Glamorgan Clyne Valley, Swansea Llanwrtyd Wells Burpham, Surrey Wheatfen Broad Singleton, Swansea . Sketty, Swansea Singleton, Swansea . Porteynon, Glamorgan Date Formula Central tooth (mm) Agriolimax reticulatus (Miiller) 2o.vii.46 20 . vii . 46 17. viii. 46 . .14.22x86 .17.27x107 . .14.22x88 0-043x0-022 ? 23 . viii . 46 . 7 . ix . 46 i8.xi.38 . .14.21x100 .16.22 .17.26x100 .6.8 0-035 xo-oi7 0-049 x 0-024 0-043x0-022 29.xii.46 . .18.26x122 . Agriolimax agrestis (Linnaeus) 0-052x0-026 Agriolimax laevis (Miiller) io.iii.48 . .13.27x92 . .13.25x95 2 . viii . . Agriolimax caruanae Pollonera ? .x.3i . .14.50 ? .iv.32 . .14.55 ? .vii.46 C.io.? .14.55x118 0-023x0-012 0-023x0-012 0-023 xo-oi4 0-029x0-017 Small but mature. Young, 8 mm long. 17. viii. 46 . .16.23 0-038x0-019 Radula 3-2 x 1-7 mm 23 . viii . 46 . C.i6.23x 105 . 040 X 02 . 17. viii. 46 . .14.21 x 100 . 0-034x0-017 . ? .x. 4 6 . .15.24 0-038x0-019 . ? . ix . 46 .15.? 0-035x0-017 . ? .15.21 x ioo . 0-032x0-016 . Euphallic. Hemiphallic. Young, 12 mm. Radula 3-1 x 1-5 mm. Alimentary system (Text-fig. 10 A) The tabulated salivary glands lie on each side of the crop, which narrows as it enters the small stomach. The posterior loop of the intestine extends behind the stomach towards the apex of the visceral mass, which is formed by the right lobe of the liver. The rectum has a small caecum overlying the ovotestis. Reproductive system (Text-fig, n c) The brown tabulated ovotestis lies towards the rear of the visceral mass, and is partly exposed on the surface (Text-fig. 10 A). The hermaphrodite duct is short and only slightly sinuous, with a seminal vesicle at its slender termination where it enters the albumen gland. The latter is short, shaped like a mammalian liver, and ZOOL. 6, 3. 12 1 68 BRITISH SLUGS FIG. ii. Agriolimax. Distal genital ducts (x 5-3). A. A. latvis euphallic indi- vidual. B. A. laevis aphallic individual. C. A. reticulatus. D. A. agrestis. E. A. laevis apex of penial appendage, showing bifid tip and two pilasters. Cephalic retractor muscles. F. A . laevis. G & H. A . reticulatus. I & K. A. agrestis. Representative radular teeth. L. A. reticulatus (x 330). M. A. agrestis (x 330). N. A. laevis (x 330). O. A. reticulatus (x 500) from young animal 8 mm long. BRITISH SLUGS 169 pale brown in colour. The common duct, with the lobulated prostatic ribbon, is thrown into zig-zag folds. The free oviduct is short and straight, and the atrium small. The spermatheca duct arises from the atrium and expands to a narrow oval sac. The short vas deferens enters the penis beyond its apex, beneath the genital retractor muscle. The penis is narrow basally, expands to a segment containing the triangular sarcobelum, and narrows a little before the apical segment. The latter terminates in a large penial appendage which is trifid, each branch having a crenulated outline. The details of the branching vary to some extent. The branches, which are tubular, are everted and turned completely inside out during mating, as in A. agrestis and A. caruanae (see Text-figs. 12 D and E). Mating This can occur throughout the year in Britain, even in the winter months, taking place on the surface usually after dark. The pair follow one another for from half to one hour in a narrowing circle, with copious exudation of mucus. The sarcobelum is protruded and plays over the partner's body. Then the animals remain still, neck to neck with bodies curved, and each atrium and penis is everted, bringing the oviduct and spermatheca duct to the surface. Then the base of the penial appendix appears and is explosively turned inside out, the branches appearing as long thin hyaline threads. A mass of sperms enclosed in a ball of mucus is simul- taneously transferred from one partner to the other's everted mass, to which it adheres. The animals separate at once, and in a few seconds the genital complexes are invaginated and withdrawn, carrying the sperm packets with them. Development The eggs, laid about ten days after mating, are about 3 X 2-5 mm, translucent and speckled with calcareous dots which become absorbed during development. They hatch in two or three weeks, the young being 4 mm long, pale grey and trans- lucent, and like all the British species have no bands at any stage. The young grow rapidly, and in warm weather may mature in three months. During late embryonic development the caudal and cephalic vesicles can be seen pulsating through the translucent shell, when the eggs are viewed under water (see Text-fig. 18 G). In Britain several broods are produced by a pair, and 700 eggs may be produced in a season. Luther (1915) states that self-fertilization occurs in A . reticulatus isolated from birth. Ecology A. reticulatus is perhaps the commonest British slug. It prefers drier sites than A . agrestis and occurs in grass fields, root crops, hedges, gardens and rubbish heaps, and under stones and logs in woods and coppices. It is often a serious pest in gardens and allotments, devouring seedlings and green crops. Distribution (Map 15) Ubiquitous in the British Isles. Probably indigenous to most of Europe, the 170 BRITISH SLUGS Mediterranean region and the Atlantic isles, and introduced by commerce into most parts of the world. Fossil record Pleistocene to Recent. Material examined Living specimens from many places in England and Wales. Spirit material from Britain, Europe, Atlantic isles, Reunion, America and New Zealand. Agriolimax agrestis (Linnaeus, 1758) Limax agrestis Linnaeus, 1758 : 652. Sweden. Limax bilobatus Ferussac, 1819 : 74. Limax pallidus Schrenk, 1848 : 143. Notes The commonest British slug, A. reticulatus (Miiller), was formerly regarded by British authors as a variety of A. agrestis, though Luther (1915) had shown them to be distinct. It is uncertain which of many synonyms in this group of slugs belong to A. agrestis and which to A. reticulatus. First British record By Ellis (1941). The slug was found at Wheatfen Broad, Norfolk, and determined by H. Watson. Diagnostic features Agrees externally with A. reticulatus, except that it is smaller, smoother and more slender and seldom has more than a few small dark flecks. Internally, the ovotestis lies further forward, and the penial appendix is short, smooth and unbranched. External appearance Like A. reticulatus, but rather slimmer and smoother, and less pigmented. The body is pale greyish-yellow, paler on the sides, sometimes with whitish calcareous- looking spots. External variation Occasionally, a few dark flecks are present and the grooves are slightly pigmented. Shell (Text-fig. 10 G) About 3 mm long, usually with the right border slightly concave. BRITISH SLUGS 171 P allied organs (Text-fig. 10 B), retractor muscles (Text-figs, n I and K), nervous system, jaw As in A. reticulatus. Radula (Text-fig, n M) The teeth are a little smaller than in A. reticulatus, and the basal plate wider (Table I, p. 167). Alimentary system (Text-fig. 10 B) As in A. reticulatus. Reproductive system (Text-fig, n D) The ovotestis lies further forward than in A. reticulatus, near the centre of the visceral mass, and is only partly exposed on the right side beneath the rectal caecum (Text-fig. 10 B). The remainder of the reproductive system is like that of A . reticulatus, except for the apex of the penis, which terminates in a single small curved digitiform appendix. Mating As in A. reticulatus. Mating occurs in Britain in the autumn, and perhaps at other times. Luther (1915) states that this species is incapable of self-fertilization, unlike A. reticulatus. Development The eggs are laid in clusters of from ten to twenty or more. They measure from 2-2 X 2-0 to 2-5 X 2-25 mm, and are more translucent and more finely dotted with calcareous particles than those of A. reticulatus. The newly hatched young are 3-5 mm long, translucent and whitish, and have no bands at any stage. In Britain, the eggs are laid in the autumn and hatch in three or four weeks. The young mature in the following summer and autumn, and die in the late autumn after mating. In Finland, the life cycle is different (Luther, 1915), in relation to the more severe climate. The eggs are laid, and the parents die, in late August or September, while the eggs do not hatch until the following June. Thus embryonic life lasts for more than eight months in Finland and less than a month in England, while post-embryonic life lasts about three and twelve months respectively. Ecology In Britain, apparently confined to marshy carr (see Ellis, 1941) in East Anglia. Distribution (Map 16) In Britain, certainly recorded only from marshes by the Norfolk Broads : a single record of an immature specimen from North Uist (Ellis, 1951 : 196) has not been confirmed. Probably widespread in Europe, northwards to Finmark and Iceland, 172 BRITISH SLUGS though the detailed distribution is uncertain because of confusion between this species and A. reticulatus. For example, Germain (1930) describes and figures A. reticulatus under the name agrestis. Material examined Living specimens from Wheatfen Broad, Sutton Broad and Alderfen Broad, all in east Norfolk. Agriolimax laevis (Miiller, 1774) Limax laevis Miiller, 1774 : i. Frederiksdal, Denmark. Limax brunneus Draparnaud, 1801 : 104. Limax campestris Binney, 1844 : 52. Limax hyperboreus Wester lund, 1876 : 97. Agriolimax bevenoti Collinge, 18970 : 295. Notes Miiller described his slug as " totum nigrum ", except for the median area of the sole, and compared its general appearance with that of the black land planarian Rhynchodemus terrestris. However, topotypes from Frederiksdal agree with the common slug, known as A. laevis in Britain, Europe and North America, in being some shade of brown. The discrepancy in colour is not highly significant, since the present species becomes very dark when somewhat dry and contracted, and since in America it varies in colour from amber to black (Pilsbry, 1948 : 540, 548 ; Altena, 1958 : 30). Simroth (1885 : 222, pi. 9) described and figured, as forms of A. laevis from Germany, what are evidently representatives of two distinct species : those corre- sponding to the euphallic and aphallic forms of the widespread slug (his figs. 21 G and 22 H), and a larger and darker species with a hammer-headed penis (his figs. 17 c and 18 D). The latter is found principally in Germany and Poland, though it appears to have been introduced to Gotland Island, Sweden (Lohmander, in Hit.}. It has never been recorded from Denmark and Lohmander, despite his considerable experience of Danish slugs, has never found it there. Taylor's figures (1902-07, figs. 131 and 132), purporting to show the genitalia of British A. laevis, are copied from Simroth and show this second species. It seems that the name laevis can properly be retained for the species to which it has long been applied. There is no reason to transfer it to the species with the hammer-headed penis, the correct name for which is uncertain. First British record By Johnston (1838 : 154), as Limax brunneus. Diagnostic features Small size, colour light or dark brown, smooth, active. Much smaller than A. caruanae. Head and neck extend further from the mantle than in A. reticulatus. Internally distinguished from the other species by its more sinuous penis, with a BRITISH SLUGS 173 tubular caecum or appendix, and the frequent occurrence of aphallic specimens ; and from A . reticulatus and A . agrestis by the absence of a rectal caecum. External appearance (PI. 2, fig. 19) Length 1-7-2-25 cm. Light or dark brown, translucent, sometimes greenish, more or less flecked with darker spots. The respiratory orifice is less conspicuously pale- bordered than in the other species. The head and neck are thrust further forward than in A. reticulatus and A. agrestis, so that the mantle is more centrally placed, and the mantle has fewer concentric ridges. The mucus is clear, not milky. The slug is very active, and crawls rapidly. External variation The ground colour varies from pale to dark brown, with more or less darker flecking on body and mantle. Pale and dark specimens occur together at all seasons. Named varieties are var. lacustris Bonelli (in Lessona & Pollonera, 1882) ( var. maculata Cockerell, 18866), irregularly spotted with dark brown ; var. grisea Taylor (1904), grey or greenish-grey. There is also marked genital polymorphism, with euphallic, hemiphallic and aphallic individuals. Shell (Text-fig. 10 i) Relatively short and broad. Pallial organs (Text-fig. 10 D) As in A . reticulatus. Retractor muscles (Text-fig, n F) The cephallic retractor muscles arise by a long common stem, and so are less deeply divided than in the other species. The retractor penis is occasionally absent. Nervous system As in A . reticulatus. Jaw Pale golden, i mm across. Radula (Text-fig. UN) Rather fewer lateral teeth, and small ectocones on more of the external marginals, than in A. reticulatus and A. agrestis. Formula .13.26. Alimentary system The rectum lacks a caecal diverticulum, as in A . caruanae. The visceral cavity is often somewhat pigmented, though less so than in A . caruanae. 174 BRITISH SLUGS Reproductive system (Text-figs, n A and B) The dark ovotestis is less exposed than in the other species. The hermaphrodite duct is short and nearly straight, with the usual seminal vesicle at the short brown albumen gland. The female portion of the common duct is leaden grey, and the prostate yellow. The spermatheca is normally oval as in the other species, but sometimes in young examples it is globular. The penis in a euphallic individual shows four regions : a distal, narrower segment ; a wider one enclosing the triangular sarcobelum ; a twisted and contorted segment entered distally by the vas deferens, and giving attachment to the retractor penis ; and a short narrower segment (diverticulum or appendix), more or less bifid at the tip. The appendix contains two thickened pilasters, which fade out on reaching the sarcobelar segment. In the aphallic form (Text-fig, n B) prostate and spermatozoa are present, but the vas deferens fades out or ends in a little vesicle, before reaching a minute knob represent- ing the penis. Apparently the penis is always the last part to be fully developed ; but in young examples that will become euphallic the vas deferens does reach the small penis and a retractor muscle is often present. Stages can be found between this and the adult euphallic form. Babor (1894) records observations which he thought indicated that A. laevis was normally protogynous young adults being always female and middle-aged adults hermaphrodite, with some old animals attaining a purely male phase, with atrophied albumen gland and spermatheca and hyper- trophied penis. He states that in the young stages sperms are very few, and there is no sperm duct or penis. However, dissection of many British examples, taken at various sites and different seasons, shows that here sperms, prostate and vas deferens are always present ; though in animals that will eventually be aphallic the vas deferens ends blindly. No example has been seen in which the albumen gland and spermatheca have atrophied. As these forms often occur together, in varying pro- portions in the same site at different seasons, it seems more likely that this is a case of genital dimorphism, such as occurs in Zonitoides. To establish this with certainty it is desirable that samples should be taken from the same site each month for a year, but an opportunity to do this has not occurred. Pilsbry (1948 : 539-552) gives numerous figures of similar dimorphism in the American forms of A . laevis. Mating Gerhardt (1939) says that following and circling around is omitted in A. laevis, and that the partners remain in contact before the sperms are transferred for a much longer period (up to an hour) than in the other species. Development The eggs are laid singly or in small clusters, probably at all seasons of the year, having been found in January, April and October. They are relatively large, from 1-8 x 1-5 to 2 X 1-3 mm, translucent, resilient, finely punctate, with polygonal calcareous granules. They hatch in four or five weeks. The young are 4 mm long, white and translucent, with the opaque white liver lobes showing through the integument. The head and tentacles are light pinkish-brown with a violet tinge. BRITISH SLUGS 175 After a few days, pigmentation begins at the tail and head, and gradually invades the rest of the body. Ecology A. laevis inhabits damper sites than our other slugs and is common in marshes and on the borders of ponds and rivers, but is occasionally found in drier sites, in fields and on the borders of woods. It has been seen feeding on mealy bugs infesting Streptocarpus in greenhouses. Distribution (Map 17) Probably ubiquitous in the British Isles. Its continental distribution is somewhat uncertain, because of the existence of a somewhat similar slug distinguished by a hammer-headed penis (p. 172). It is common in marshy places throughout the Holarctic, extending southwards in Europe to northern Italy. Most of this range is probably occupied by the true A . laevis, showing only slight infra-specific variation. A. laevis has been widely introduced into tropical regions and oceanic islands, where it has been recorded under many different names. For example, specimens from Hawaii in the B.M. (N.H.) labelled as A. bevenoti Collinge (Kauai) appear to belong to the aphallic form of this species, and others labelled as A . perkinsi Collinge (Lanai) and A . globosus Collinge (Mauna Loa) to the euphallic form. Fossil record Pleistocene to Recent. Material examined Living specimens from many places in England and Wales. Spirit specimens from the type locality (Frederiksdal, Denmark), kindly collected and sent to me by Dr. Mandahl-Barth, and from Britain, South America, New Zealand and Hawaii. Agriolimax caruanae Pollonera, 1891 Agriolimax caruanae Pollonera, 1891 : 3. Porta Reale, Malta. Notes Pollonera described the keel of his species as blackish, and figured a more globular spermatheca than is found in adult British specimens. However, in Britain the keel and head are the first parts to pigment, so that in young animals they are darker than the rest of the body. The spermatheca is sometimes globular, in young animals at any rate in Britain, and in adults of some American forms. Pilsbry (1948 : 558) figures considerable variation between American specimens, which he nevertheless recognizes as belonging to A . caruanae. The British slug can be at most a geographical race of this species, of which Quick (1949 : 28) gives a short account. I 7 6 BRITISH SLUGS FIG. 12. BRITISH SLUGS 177 First British record Specimens, found by the late Charles Oldham in Cornwall about 1930, were identified with this species (as perhaps a distinct subspecies or variety) by H. Watson, and exhibited at meetings of the Conchological Society of Great Britain and Ireland and the Malacological Society of London. Diagnostic features Distinguished in life from the externally similar A . laevis by larger size and even greater activity. Internally distinguished by having two penial diverticula and a tuft of appendages, a darkly-pigmented visceral cavity, and a greater number of marginal radular teeth. External appearance (PL 2, fig. 17) The length when extended is 2-5-3 cm > r a little more. As in A. laevis, the head and neck extend far beyond the mantle. The slug is dark translucent chestnut brown, greyish-brown or grey, with the mantle lighter over the pallial region, and the body and mantle more or less flecked with dark brown. The respiratory orifice is pale rimmed. The sole is grey rather than brown, because the dark visceral pig- mentation shows through the tissues. The mucus is thin and colourless. External variation The colour varies from a clear chestnut-brown to a greyer brown, and the small darker flecks on body and mantle are more or less marked, but there are no named varieties. Shell (Text-fig. 10 H) 4-5 X 2 mm, or a little larger. In undistorted specimens, the right border is slightly concave. Pallial organs (Text-fig. 10 E) As in A . reticulatus. FIG. 12. Agriolimax caruanae. A. Reproductive organs (x 4). B. Penis ( X 14) opened to show sarcobelum, two diverticula, entries of vas deferens and crenu- late branched appendix, penial retractor. C. Penis (x 8). D. Sarcobelum protruded, atrium everted, appendix beginning to be everted. E. Three branches of appendix fully everted, sarcobelum beginning to shrink. F. Distal genital ducts ( x 30) of young individual 1 1 cm long, showing oviducts, spermatheca, sarco- belum in penis, rudiments of diverticula and appendix. G & H. Cephalic retrac- tors. The buccal retractor is sometimes completely divided. I. Ganglia and commissures of nerve ring. K. Jaw (x 20). L. Representative radular teeth (x 500). M. Jaw ( x 100) of individual one day old. N. Jaw ( x 100) of young individual 6 mm long. 178 BRITISH SLUGS Retractor muscles (Text-figs. 12 G and H) The cephalic retractors arise by a common stem, and the buccal retractor is divided either completely or for half its length. Nervous system (Text-fig. 12 i) As in A . reticulatus. Jaw (Text-fig. 12 K) Of the usual oxygnathous type, 1-3 mm across. In the newly-hatched animal, a median indentation (like that seen in Milax, Limax and Vitrina] reveals a bilateral origin (Text-figs. 12 M and N). Radula (Text-fig. 12 L) Characterized by having rather fewer lateral teeth and more marginals than A. reticulatus and A. agrestis. Formula 0.14.55. Alimentary system (Text-fig. 10 c) As in A. laevis, there is no rectal caecum. The walls of the visceral cavity are darkly pigmented. Reproductive system (Text-figs. 10 c and 12 A-F) The dark ovotestis lies rather far forwards, and is partly exposed on the left side of the visceral mass. The oviduct, atrium and spermatheca require no special comment. The basal segment of the penis is slender and the segment containing the sarcobelum capacious. The distal segment bears apically two curved hollow processes, of which the left is often the longer, and between these an appendix with four or five long slender crenulated branches, corresponding with the apical appendix of A. reticulatus. Mating (Text-fig. 10 K) Breeding occurs throughout the year, eggs having been seen in January, May, June, July, October, November and December. A mating pair was observed on 25th June, 1950. At 6.10 p.m. the partners were following one another in a circle, with protruded sarcobela, licking one another's tails. At 6.40 they were lying quietly with their necks close together, with the atria everted and the sarcobela shrinking. A few seconds later, the four long tubular branches of the penial appendices were everted, lying across the partner's body like hyaline threads. At 6.42 the everted organs were rapidly withdrawn, with the sarcobela last, and the animals crawled apart. Individuals from Glamorgan and Denbigh, isolated from birth, have on several occasions been seen to lay a few self-fertilized eggs, which have developed to an advanced stage although they have not been seen to hatch. Gregg (1944) reports fertile eggs from virgin specimens in California. There this species (for which Gregg BRITISH SLUGS 179 uses the name Deroceras panormitanus] apparently passes through a purely female phase when about half grown. Only about half the individuals survive this phase, to grow to full size and develop male organs. There is no sign of such a female phase in Britain, where slugs only 10 mm long, with their common ducts still slender and immature, always have penes in which the rudiments of all the adult features are easily recognizable. Two diverticula, a budding tufted appendix and a sarcobelum can be seen in a penis between 1-3 and 1-6 mm long. Aphallic and hemiphallic individuals are unknown in Britain. In any case, aphallic individuals of A. laevis are not in a female phase, since they have spermatozoa and a prostate. Gregg's observations are explicable in two ways : he may possibly have been working with a mixed culture of A . caruanae and A . laevis, or the difference may be related to the more rapid development of A. caruanae in California than in Britain. Development The eggs are relatively small, from 1-5 x 1-5 to 175 x 1-4 mm : much smaller than those of A . reticulatus and A . agrestis, and not much larger than those of A . laevis. They are laid in clusters of up to fifty eggs, and in the summer hatch in about seven- teen days. The young are only about 3 mm long, very pale and translucent, with pale violet tentacles. Pigmentation begins at the head and tail, as in A . laevis. Behaviour A . caruanae crawls extraordinarily fast for a slug, and is irritable and pugnacious, snapping at its neighbours and lashing its tail. Even when well supplied with food, it shows cannibalistic tendencies. Ecology Usually confined to gardens, in flower and vegetable beds, lawns, rubbish heaps and greenhouses ; but occasionally found at a distance from houses, in hedges, fields and waste places (records from Devon and Glamorgan). Distribution (Map 18) Recorded from scattered localities in England (mainly in the west), Wales, Scotland and southern Ireland (Makings, 1959). The extra-limital distribution is very imper- fectly known. Repeated efforts to obtain topotypes from Malta have failed. The species probably occurs at Marseilles (Pilsbry, 1948 : 560), and has been introduced into California. Fossil record Holocene shells from Romney Marsh (Hayward, 1954^ and b) are very suggestive of this species. Although slug shells are badly characterized, especially when fossil, there is a prima facie case for believing that these are indeed shells of A. caruanae. Otherwise, the species is known only from Recent deposits. Material examined Living or spirit specimens from St. Agnes, Scilly Isles ; Exeter, Devon ; Swansea i8o BRITISH SLUGS and Porteynon, Glamorgan ; Old Colwyn, Denbighshire ; St. Albans, Hertfordshire ; Bromborough, Cheshire ; Edinburgh and Aberdeen, Scotland ; Cork (grounds of the University, from Dr. Makings) and Newcastle, Co. Down (Dr. Stelfox's garden), Ireland ; Pyrenees Orientales ; Golden Gate Park, San Francisco. Genus LIMAX Linnaeus, 1758 Type species Limax maximus Linnaeus, 1758. Limacinae in which the right ocular retractor passes forwards between the penis and the vagina. The intestine has two forwardly-directed loops, and the left lobe of the liver forms the apex of the visceral mass. There is no penial stimulator. The nucleus of the concentric mantle ridges lies in the mid-dorsal line. The dorsal keel slopes evenly to the end of the tail, which is therefore pointed and not truncated. Hesse (1926 : 8-16, 76-92) divides Limax into several subgenera, and the nominate subgenus into sections. Since no regular trends in several characters are discernible, each species being specialized in some respect or another (e.g. the long penis and peculiar mating behaviour of L. maximus and L. cinereoniger) , the infrageneric arrangement depends largely on the relative systematic importance attached to the radula, penis, alimentary tract and other organs. For example, L. nyctelius may be associated with L. flavus in the section Limacus, on the basis of its rather long cylindrical penis and long rectal caecum ; but their radulae are very different, that of L. flavus being specialized in the suppression of ectocones and endocones, while that of L. nyctelius approaches the condition of Agriolimax. Subgeneric and sectional names are therefore not adopted here. Limax tenellus Muller, 1774 Limax tenellus Muller, 1774 : n. Denmark. Limax tenellus; Nilsson, 1822 : n. Limax serotinus Schrank, 1848 : 144. Limax cereus Held, 1849 : 15. Limax fulvus Normand, 1852 : 7. Agriolimax tenellus', Lessona & Pollonera, 1882 : 45, pi. i. fig. 7. Notes Although Nilsson is often quoted as the author of this name, it was first applied by Muller. Ignoring an obvious mistake in measurement, Miiller's description seems adequate to identify the present species : " Limax virescens, capite tentaculisque nigris. Dan. SP^ED-SNEGLEN. long. 10 unc. Totus albidus, Clypeus in luteum, abdomen in virescentem colorem aliquantum vergit ; ille margine postico, hoc apice supra nigricat. In Fossulis Nemorum foliis aridis repletis ; primo vere." Altena (1958) confirms that L. fulvus Normand is indeed L. tenellus. First British record By Alder (1848 : 124). BRITISH SLUGS 181 Diagnostic features Distinguished externally from other British species by small size, and pale yellow colour, with black head and tentacles ; and internally by a short penis with no appendix. External appearance (PI. 2, fig. 16) The smallest British Limax, from 25 to 35 mm long when extended. Colour pale yellow, or sometimes reddish-brown, with blackish head and tentacles, and sometimes with a pair of more or less distinct body and mantle bands. The mucus is yellow. External variation Var. cerea Held (1849), uniform yellow, or with mere traces of bands ; var. fulva Normand (1852), reddish-brown, suffused dorsally with black ; var. cincta Heyne- mann (1861), with distinct dark mantle bands, and sometimes body bands. Shell Thin and delicate, measuring about 3-5 x 2 mm. Pallial organs (Text-fig. 13 D) The somewhat angularly crescentic kidney partly embraces the heart and peri- cardium, just behind the origin of the penial retractor. Retractor muscles (Text-fig. 13 E) The cephalic retractor arises by two roots in the mid-dorsal line just behind the kidney, and divides about half-way along into right and left tentacular retractors. The right tentacular retractor passes forwards between the penis and oviduct, and not on the left of both as it does in Milax and Agriolimax. The pharyngeal retractor arises half-way along the left tentacular retractor, and divides into right and left branches passing to the buccal bulb between the cerebral and visceral ganglia. The penial retractor arises from the diaphragm on the left side, in front of the pericardium. Nervous system (Text-fig. 13 H) The olfactory and optic lobe of the cerebral ganglion is large, the cerebro-pleural and cerebro-pedal commissures short, and the visceral ganglia closely approximated, the right visceral and abdominal ganglia being fused together. Jaw (Text-fig. 13 F) Of the usual oxygnathous type, 1-5 mm across. Radula (Text-fig. 13 G) The central tooth, 0-038 X 0-018 mm, with small but distinct ectocones, is flanked on each side by about twenty lateral teeth with both ectocones and endocones, 1 82 BRITISH SLUGS followed by about forty-five marginal teeth. The teeth between the eighteenth and twenty-second are transitional in character, the endocone diminishing, and the ectocone approaching the mesocone. In the marginals, the mesocone becomes relatively longer and more curved, and the ectocone becomes prominent, arising from the side of the mesocone. Ectocones occur in some of the outer marginals of other Limax species, but they are not the conspicuous feature throughout that they are in L. tenellus. Formula .20.45 x no. FIG. 13. Limax tenellus. A. Reproductive organs (x 4). B. Penis (X 6-7) opened. G. Alimentary system, showing left lobe of liver forming apex of visceral mass, ovotestis at stomach level, between left and right lobes, intestine, cephalic retractor, oesophagus, salivary glands, buccal bulb, portion of albumen gland below left liver lobe. D. Kidney, heart and pericardium, origin of penial retractor in front, second forwardly-directed loop of intestine passing around cephalic retractor, rectum. E. Cephalic retractor muscles. F. Jaw ( x 14). G. Represent- ative radular teeth ( x 330). H. Nerve ganglia (x 8). BRITISH SLUGS 183 Alimentary system (Text-fig. 13 c) The left lobe of the liver forms the apex of the visceral mass. The apex of the stomach forms the most posterior part of the alimentary tract (which in Limax has almost lost the spiral torsion seen in Avion and in Milax), and the intestine has two forwardly directed loops. The first of these is held in place by the aorta as usual, and the second, which extends further forwards, is crossed by the cephalic retractor. The intestine runs backwards from this point and turns sharply to run forwards as the rectum, between the cephalic retractor and the floor of the pulmonary chamber, to the posterior lip of the respiratory orifice. Reproductive system (Text-fig. 13 A) The darkly pigmented ovotestis lies behind the stomach, but a little of it may be visible from the dorsal aspect, between the right and left lobes of the liver. The dilated central part of the hermaphrodite duct is pigmented and sinuous, narrowing at the albumen gland, where it has a distinct unpigmented vesicula seminalis. The prostate does not diverge anteriorly from the oviduct. The short vas deferens, which is not bound down by the right ocular retractor, becomes sacculate and pig- mented at the entrance to the penis, apically above the insertion of the penial retractor. Internally the penis (Text-fig. 13 B) shows three or four delicate short transverse folds apically, and further forwards three main massive longitudinal folds, the exact appearance varying according to where the penis is opened. These folds are visible during copulation (see below). The spermatheca is small and club- shaped, with a short duct entering the atrium. Mating According to Gerhardt (1933 : 445), one animal follows the other rapidly, head to tail. The leader soon bends to the right, so that after ten minutes the circle is completed. The penes are suddenly everted as massive bluish-white bodies, each with a thickened oblique fold which Gerhardt calls the comb. The penes are closely apposed, but not entwined, and the animals slowly revolve clockwise for one and a half hours. L. tenellus differs from L. maximus and L. cinereoniger in not entwining the body nor hanging from a horizontal surface. Development The eggs vary from 3-6 x 3-1 to 3-3 X 3-0 mm, and are pale amber, soft, trans- lucent and slightly adherent. In Britain, they are laid from November to March in clusters of about fifteen, and take from sixty to 120 days to hatch. The young are 6 mm long, with a slight dorsal keel posteriorly. They are white and translucent, without body and mantle bands and with a more opaque kidney region. The tentacles are pale violet, with the dark brown retractor muscle showing through. Ecology Restricted to woodlands, usually of considerable extent, and one of the few slugs found in pine woods. Absent from most of the many woods and plantations ZOOL. 6, 3. 13 184 BRITISH SLUGS established during the seventeeth century, which suggests that its powers of dispersal are poor. Indifferent to the presence or absence of lime. Distribution (Map 19) Of very local occurrence, though wide range, and therefore seldom encountered. In Britain, recorded from many vice-counties. In Europe, found from France northwards to Jemtland, and eastwards to the Caucasus. Material examined Living specimens from Netley Heath, Shere, Surrey ; and Chepstow, Monmouth- shire. Spirit specimens from Britain and Switzerland. Limax flavus Linnaeus, 1758 Limax flavus Linnaeus, 1758 : 652. Sweden. Limax variegatus Draparnaud, 1801 : 103. Limax megalodontes Quoy & Gaimard, 1824 : 426. First British record By Lister (1685-97, pi- ^-^ib). Diagnostic features Tentacles steely blue, body and mantle with yellowish spots and no lateral bands. Long rectal caecum and long cylindrical penis a diagnostic combination for British Limax. External appearance (PI. 2, fig. 22) A rather large slug, from 7 to 10 cm long when extended. Colour from yellowish to greenish, more or less suffused with dusky pigment, and mottled on the mantle with yellow patches, on the body with yellow spots formed by groups of up to seven tubercles. There are no lateral bands. The tentacles are a very characteristic cold steely blue, the sole pale yellow, the respiratory orifice pale-rimmed, and the mucus yellow. External variation Var. rufescens Moquin-Tandon (1855), reddish-brown ; var. virescens Ferussac (1819), uniformly greenish ; var. antiquorum Sowerby (1834 ?)> P a l e ochraceous marbled with grey ; var. breckworthiana Lehmann (1864), uniformly suffused with dark pigment. Shell Rather large, 9x6 mm, thin and convex, with the nucleus near the posterior margin and a little to the left of the mid-line. BRITISH SLUGS 185 Pallial organs As in L. tenellus. Retractor muscles (Text-fig. 14 D) The cephalic retractors arise from two roots, which do not unite for a considerable distance. The buccal retractor arises near the origin of the left ocular retractor. The penial retractor arises from the diaphragm, in the region of the kidney. A c B FIG. 14. Limax flavus. A. Alimentary system ( x 2) showing second forwardly- directed loop of intestine passing around cephalic retractor, long rectal diverticulum passing backwards. B. Reproductive organs (x 2). C. Penis (x 6) opened to show internal folds. D. Cephalic retractor muscles. E. Jaw (x 14). F. Representative radular teeth ( x 330). i86 BRITISH SLUGS Nervous system As in L. tenellus. Jaw (Text-fig. 14 E) 2-25 mm across, dark brown in colour. Marked transversely with fine striae, which are crossed by still finer ones following the contour of the jaw. Radula (Text-fig. 14 F) Measures 6-5 X 2-6 mm, with about 150 rows of teeth. The central tooth (measur- ing 0-05 X 0-038 mm) has a strong mesocone, but its ectocones are obsolete or absent. The lateral teeth are also devoid of ectocones and endocones. The aculeate marginals, some of the outermost of which have small ectocones, are connected to the laterals by several transitional teeth. Formula .16+4.50 X 150. Alimentary system (Text-fig. 14 A) The oesophagus dilates to a capacious crop, flanked by the salivary glands, and merging gradually into the stomach. The second forwardly directed loop of intestine is held in place by the cephalic retractor muscle. Instead of being prolonged back- wards as it is in L. tenellus, it soon turns forwards as the rectum ; but from the apex of the bend a long rectal diverticulum extends backwards, on the surface of the liver, to the end of the body. As in the other species of Limax, the left liver lobe forms the apex of the visceral mass. Reproductive system (Text-fig. 14 B) The unpigmented ovotestis lies between the lobes of the liver, well below the stomach apex. The hermaphrodite duct, at its entrance to the yellow linguiform albumen gland, has a rounded white seminal vesicle. The ribbon-like yellow prostate diverges from the oviduct anteriorly, and can easily be peeled off it for the greater part of its length. The vas deferens runs forward, and turns back beneath the right ocular retractor to the apex of the penis. The penis is a rather long cylindrical organ, strongly folded in a spiral. Internally it bears (besides three or four minor longitudinal folds) a long, low, crinkled, ribbon-like fold along its whole length, and another more prominent fold that expands distally to a crest or " comb ", lobulated or crenulated on the free margin (Text-fig. 14 c). The oviduct expands at its entrance to the atrium, where the spermatheca arises from it. Mating Mating occurs from late summer to February. According to Gerhardt (1933), after " following " for about eight minutes, the animals approximate the right sides, but do not curve into a circle. The penes are rapidly everted and entwine spirally, forming a mass of about one square centimetre in area. Sperms enclosed in a mucous mass are transferred between the penes, which are rapidly withdrawn carrying the partner's sperms with them. The whole process occupies only half BRITISH SLUGS 187 a minute. Gerhardt does not state what follows, but presumably the sperms are transferred from the withdrawn penes to the spermathecae. Development The eggs are laid in clusters of up to twenty, and have been found in September and February. They are large, 6x4 mm, pale amber in colour, and differ from those of other British slugs in having a small rounded projection at each end, so that they resemble miniature lemons. They hatch in from three to six weeks at room temperatures. The newly-hatched young are from 10 to 13 mm long, pale greenish-yellow with the characteristic blue tentacles already evident. There are no bands at any stage, and the yellow spots of the adult appear later in development. Behaviour L. flavus is essentially nocturnal, and unless looked for after dark it may escape observation in urban surroundings, even where it is abundant. Ecology L. flavus is found in woods, under logs and bark, but is much commoner in gardens, in the crevices of walls, and in cellars and out-houses. It eats decaying vegetable matter, fungi and lichens in wild places, and mildew and garbage in gardens and out-houses. Distribution (Map 20) Probably occurs in every vice-county of the British Isles, and ranges from southern Norway to North Africa and eastwards to Syria. It has been introduced into South Africa, Australia and North and South America, and to islands in the Atlantic and Pacific. Material examined Living specimens from Swansea, Glamorgan ; and Reading, Berkshire. Spirit specimens from Britain, Corsica, Greece, North and South America, South Africa, Australia, and the New Hebrides and Cook Islands. Limax cinereoniger Wolf, 1803 Limax cinereoniger Wolf, 1803 : 7. Germany. Limax antiquorum F6russac, 1819 : 68 (in part). Limax maximus', Gray, 1840 : 113 (in part). Avion lineatus Dumont, 1850 : 64. Limax cinereus var. intermedia Breviere, 1881 : 314. First British record By Gray (1840). i88 BRITISH SLUGS Diagnostic features Largest British slug, usually black with dorsal line and median zone of sole white, keel prominent and rather long. Distinguished from L. maximus by coloration, and by coarser tubercles, spotted tentacles, relatively small shell and jaw, and longer penis not tapering distally. External appearance (PI. 2, fig. 25) This is our largest native slug, which grows to 10 or 20 cm long in this country, while some continental forms are even larger. The keel is prominent and long, and the tubercles relatively coarser than in L. maximus. The slug is usually black all over, except for the white mid-dorsal line and median area of the sole. The dark tentacles are spotted with small discrete black or dark brown dots a character distinguishing the species from L. maximus, which has apparently not been recorded previously. External variation In Britain the ground colour, seen in the mid-line and the median area of the sole, is usually whitish, but in continental specimens the keel may be red or yellow. The following named varieties have been recorded from Britain : var. ornata Lessona (1880), body black with a series of white spots along each side ; var. maura Held (1836), entirely black ; var cinerea Moquin-Tandon (1855), entirely ash-coloured except for bluish-black mantle ; var. punctata Lessona (1880), keel and mid-line of dorsum yellow, two interrupted bands on each side. Shell Relatively smaller (9x5 mm), thinner and slightly more elongated than that of L. maximus. Pallial organs As in L. tenellus. Retractor muscles The slender cephalic retractor arises from the mid-line behind the diaphragm, and crosses the second forwardly-directed intestinal loop. The right ocular retractor passes (as is usual in Limax] between the male and female divisions of the distal genital ducts, over the vas deferens. The penial retractor arises broadly from immedi- ately to the left of the cephalic retractor, and narrows to its insertion at the apex of the penis. Nervous system As in L. tenellus. BRITISH SLUGS 189 Jaw (Text-fig. 15 E) Usually about 3 mm across, but may reach 4 mm in very large specimens : relatively smaller than in L. maximus. 23 1*0 bo bq 23 40 60 70 H FIG. 15. Limax. A. L. cinereoniger distal genital ducts ( x 1-3). B. L. maxi- mus mating pair suspended from mucus thread (adapted from L. Adams). C. L. maximus distal genital ducts (x 2). D. L. maximus stages in eversion and entwining of penes (adapted from L. Adams). E. L. cinereoniger jaw (x 6-7). F. L. maximus jaw (x 6-7). G. L. cinereoniger representative radular teeth ( x 33) H. L. maximus representative radular teeth ( x 330). igo BRITISH SLUGS Radula (Text-fig. 15 G) There are about 150 rows of teeth. The central tooth has rather small but strong ectocones. It is flanked by about nineteen laterals, with ectocones and endocones, the latter descending on the mesocones in the outer teeth. There are about fifty marginals on each side, of which only the inner teeth retain the endocone. In the outer marginals, an ectocone appears on the concave side of the mesocone, and becomes bifid or trifid in a few of the outermost teeth. Formula .19.50 x 150. Alimentary system Resembles L. tenellus, and differs from L. flavus, in having the loop of intestine which is retained by the cephalic retractor prolonged backwards almost to the visceral apex, and without a rectal caecum. The loop is longer than in L. maximus. Reproductive system (Text-fig. 15 A) The long narrow darkly pigmented ovotestis is visible on the surface between the left and right liver lobes. The hermaphrodite duct is pale, slender at first, then wider and folded, and narrows at the somewhat triangular albumen gland. If a seminal vesicle is present, it is small, deep in the albumen gland and difficult to find. The folded common duct narrows to a long free oviduct, dilated at its entry into the atrium, and the small club-shaped spermatheca arises one or two millimetres before its end. The prostate separates from the common duct and so is free at its anterior end, and the vas deferens passes under the right ocular retractor and back to the apex of the penis. The stout cylindrical contorted penis is of nearly uniform diameter throughout its length, and when straightened out is from 6-8 cm long. Internally it bears a prominent fold, double at its origin. In its upper part this expands into a prominent frill, the " comb ". The rest of the mucous membrane is circularly ridged. Mating Mating occurs at night, throughout the milder periods of the year, on vertical or overhanging surfaces. After about fifteen minutes of " following ", the animals hang down freely from a disk of mucus. Their bodies and the evaginated penes, which become as long as the bodies, are entwined. A mass of sperms enclosed in mucus descends each vas deferens inside the penis, and the sperm packets are exchanged between the "combs" which are now terminal. The penes are then withdrawn, carrying the sperms with them to be transferred later to the spermathecae. The whole process takes about twenty minutes. Auto-fecundation can occur in this species (Oldham, 1942^). Development The eggs are about 5 X 5-5 mm, soft, translucent and amber-coloured. On account of the large size of the eggs, and their transparency when under water, the caudal and cephalic vesicles of the embryos can easily be observed (Text-fig. 18 H). The BRITISH SLUGS 191 eggs hatch in about a month. The newly hatched young are translucent white, but soon become opaque, then brown and finally black. There is sometimes a sug- gestion of banding, and the lateral areas of the foot are the last to pigment. Oldham (1942^) records that this slug becomes mature in two years, and that an individual in captivity lived for five years and 270 days. Ecology This is essentially a slug of wild places, being found beneath logs and leaves and in tree crevices of ancient woodlands. In Pembrokeshire at least, it also occurs on damp lichen-covered rocks on bare hillsides. It seems never to occur in gardens and cultivated land or recent plantations. Though in the wild it presumably feeds on lichens, fungi and decaying vegetable matter, in captivity it readily eats carrot, oatmeal etc. Distribution (Map 21) L. cinereoniger is recorded from most British vice-counties, except for East Anglia and parts of central England, southern Scotland and central Ireland. In Europe, it extends from arctic Norway to north-eastern Spain, Italy, Sardinia, Greece and the Crimea. Material examined Living specimens from Netley Heath, Surrey ; Cusop Dingle, Hereford ; Buckle- bury, Berkshire ; and Pont Neath Vaughan, Glamorgan. Spirit material from Britain, Denmark, Germany and Luxemburg. Limax maximus Linnaeus, 1758 Limax maximus Linnaeus, 1758 : 652. Sweden. Limax cinereus Miiller, 1774 : 5. Limax antiquorum F6russac, 1819 : 68 (in part). First British record By Lister (1674 : 99). Diagnostic features Large, differs from L. cinereoniger in coloration : grey or brown with two or three bands on each side of body, dark spotting or marbling on mantle, tentacles pale pinkish-brown without spots, sole uniformly pale ; and also in having the tubercles relatively smaller, the shell and jaw relatively larger and the penis shorter and tapering distally. External appearance (PI. 2, fig. 24) Length from 10 to 20 cm. The tubercles are relatively smaller than in L. cinereoniger. The slug is usually some shade of grey, with a uniformly pale sole. IQ2 BRITISH SLUGS The body bears two or three bands, often doubled or more or less interrupted, on each side. The mantle is irregularly spotted or marbled with dark pigment, but never banded. The tentacles are translucent pinkish-brown, without spots. External variation The ground colour may be grey, ochraceous or reddish, and the bands may be developed to an infinitely variable degree. Named varieties are : var. concolor Pini (1876), uniformly ash-coloured ; var. Candida Lessona & Pollonera (1882), white, translucent, eyes pale brown ; var. vinosa Baudon (1884), purple or vinous brown ; var. fasciata Razoumowsky (1789), ash-coloured with three bands on each side ; var. sylvatica Morelet (1845), ash-coloured with two bands, and an indistinct third lower band ; var. tetrazona Taylor (1902), with only two bands on each side ; var. cellaria Dezallier d'Argenville (1742), bands interrupted ; var. aldrovandi Moquin-Tandon (1855), ash-coloured with pale spots ; var. tigris Taylor (1902, from Adams MS.), tawny yellow with black bands. Shell Measures about 11x7 mm, and is thus relatively larger than that of L. cinere- oniger. Pallial organs, retractor muscles, nervous system As in L. cinereoniger. Jaw (Text-fig. 15 F) Relatively larger (3-5 mm across) than that of L. cinereoniger. Radula (Text-fig. 15 H) The central tooth is larger and relatively narrower than in L. cinereoniger, and its ectocones are more delicate and sometimes almost obsolete. There are about nineteen lateral teeth on each side, all or most of which retain both ectocones and endocones. The marginals (about fifty on each side) lack endocones, and only some of the outermost teeth have small ectocones. Formula 0.19.50. Alimentary system As in L. cinereoniger, except that the last posteriorly-directed loop of intestine is shorter, reaching only about half-way along the visceral mass. There is no rectal caecum. Reproductive system (Text-fig. 15 c) The ovotestis is of the same long flattened linguiform shape as in L. cinereoniger, but is pale or only slightly pigmented. The hermaphrodite duct, albumen gland, common duct, free oviduct and spermatheca are also similar. The distal end of the prostate diverges more or less from the oviduct, and above this the prostate is BRITISH SLUGS 193 only weakly attached for a considerable distance. The penis differs from that of L. cinereoniger in being shorter, widest apically and tapering distally. Internally there is a fold, expanded proximally into a " comb ", as in L. cinereoniger. Mating (Text-figs. 15 B and D) This occurs at night from overhanging surfaces. Unlike L, cinereoniger, L. maximus hangs suspended in mid-air from a stout thread of mucus. The protrusion of the organs, sperm transfer, and withdrawal of the penes is as in L. cinereoniger, but the entwined penes are not so long. After withdrawal, the animals re-ascend the mucus thread. Adams (1898) gives further details. Development The eggs, 5-0 x 5-5 mm, resemble those of L. cinereoniger. They are laid in early spring and in the autumn. February eggs in an unheated room hatch in six and a half weeks. The young are pale grey, with the middle lateral bands visible from hatching thus differing from young Lehmannia marginata, in which the upper band appears first and mantle bands are also present. The tentacles are pale pinkish- grey. After two or three weeks, the other body bands have appeared and begin breaking up, and the mantle becomes marbled. L. maximus lives for at least three or four years. Ecology L. maximus occurs in woods, hedgerows and waste places, where it is sometimes found together with L. cinereoniger ; but unlike the latter it occurs also in gardens, cellars and out-houses. It seems to avoid green leaves and to feed on fungi and decaying matter, though in captivity it readily eats oatmeal, Bemax etc. Distribution (Map 22) Apparently general in the British Isles, and found from Oslo and Petrograd to Asia Minor, Algeria and the Atlantic isles. Introduced into North America, South Africa, Australia, Tasmania and New Zealand. Material examined Living specimens from Swansea, Glamorgan ; Savernake Forest, Wiltshire ; Bucklebury Common, Berkshire. Spirit material from Britain, France, Greece, Azores, Madeira, Canary Isles and British Columbia. Genus LEHMANNIA Heynemann, 1861 Type species Limax marginatus Miiller, 1774. The penis is short, with a laterally-placed apical appendix (conical in L. marginata, short and cylindrical in L. poirieri, and long and cylindrical in L. melitensis Lessona & Pollonera). A long rectal caecum extends to the apex of the visceral mass. In 194 BRITISH SLUGS L. poirieri and L. melitensis the radula is like that of Agriolimax ; but that of L. marginata is highly specialized. The body readily absorbs water and becomes swollen and translucent. Hesse (1926) adopts sectional names within Lehmannia, segregating L. marginata (Lehmannia s.s.) from L. poirieri and L. melitensis (Ambigolimax] because of the former's specialized radula, although their reproductive and alimentary systems are very similar. As for Limax, subdivision of the genus depends on the importance ascribed to different characters. Lehmannia marginata (Miiller, 1774) Limax marginatus Miiller, 1774 : 10. Denmark. Limax arborum Bouchard-Chan tereaux, 1837 : 164. First British record By the Reverend B. J. Clarke (in Thompson, 1840 : 204). Diagnostic features Gelatinous aspect in damp weather, mantle bands forming lyre-shaped figure, two body bands on each side ; conical penial appendix, rectal caecum, specialized radula. External appearance (PI. 2, figs. 18 and 21) Usually about 7-5 cm long, or larger. Its great capacity for absorbing water makes this slug become semi-transparent and gelatinous in appearance during damp weather. When irritated, it exudes copious watery mucus. In colour it is character- istically grey with a pale sole, two darker body bands on each side (which may be more or less indistinct or interrupted), and a pair of mantle bands forming an elongated lyre-shaped figure. The keel is paler than the body, and the median area of the mantle often darker. External variation Var. glauca Clarke (1843), ground colour greenish-grey ; var. subrufa Le Compte (1871), ground colour yellow ; var. rosea Broeck (1870), ground colour pinkish ; var. bettonii Sordelli (1870), body bands fused together and interrupted; var. tigrina Wienland (1876), with rows of black spots on body and mantle ; var. rupicola Lessona & Pollonera (1882), darkly pigmented, with indistinct markings. Shell White and iridescent. Normally measures 4 X 2-75 mm, but varies considerably in size and thickness. Pallial organs As in Limax, BRITISH SLUGS 195 Retractor muscles (Text-fig. 16 c) The main stem of the cephalic retractors arises from the mid-dorsal line just behind the kidney, and divides about half-way into the right and left ocular retractors. The buccal retractor arises from the left ocular retractor, a short distance in front of the bifurcation. The strong penial retractor arises from the diaphragm between the pericardium and the posterior border of the kidney, to be inserted below the vas deferens. 15 50 51 10 FIG. 1 6. Lehmannia marginata. ( X 5-3) opened longitudinally, tract and salivary glands. E. (X 330). A. Reproductive organs (x 3-3). B. Penis G. Cephalic retractor muscles. D. Alimentary Jaw ( x 13). F. Representative radular teeth ig6 BRITISH SLUGS Nervous system As in Limax. Jaw (Text-fig. 7 E) 1-4 mm across, pale yellow in colour, and of the usual Limacid shape, not as narrow as figured by Taylor (1902-07, fig. 106). Radula (Text-fig. 16 F) Very characteristic, and easily distinguishable from the radulae of other British slugs. The central tooth has a strong, broad and short mesocone, and very small or obsolescent ectocones. It is flanked by ten or eleven laterals, with short wide mesocones and no ectocones, of which only the innermost one or two may have small endocones. The numerous marginals (up to seventy on each side) have charac- teristically strong, arched reflections bearing the short wide mesocones. From about the fortieth marginal outwards, the mesocone becomes bifid and then trifid, and minute denticulations corresponding to ectocones appear on the reflection. Alimentary system (Text-fig. 16 D) Resembles that of Limax flavus, with a rectal caecum extending backwards on the surface of the liver to the level of the stomach apex. The visceral cavity is darkly pigmented. Reproductive system (Text-fig. 16 A) The ovotestis is bulky and compact and superficially pigmented. The hermaphro- dite duct is pale, swollen and folded in its median portion, and bears a rounded seminal vesicle where it terminates at the short linguiform albumen gland. The oviduct and spermatheca resemble those of Limax. The prostate is extraordinarily massive and deeply pigmented. The vas deferens, bound down by the right ocular retractor muscle, is short and wide, and enters the penis at the side of its blunt apex. At the opposite side of the apex there is a short conical appendix. The penis opened longitudinally (Text-fig. 16 B) shows a prominent fold, expanded and free at the apex and almost smooth, but corresponding with the " comb " of Limax. There is a small conical fold at the entrance to the appendix. The walls of the proximal part of the penis are thick and rugose. Mating This species can mate on level, vertical or overhanging surfaces. Development In Britain, mating occurs during the winter months. December eggs in an unheated room hatch in February. The eggs are soft, very translucent and pale amber in colour. They usually measure 4-3 X 3-6 mm, but some are smaller. The young are 10 mm long, pale translucent grey with violet tentacles. They show well-marked BRITISH SLUGS 197 lyriform mantle bands, and a distinct band high up on the body in contrast to young Limax maximus, in which the middle band is the first to appear. Behaviour Like many (perhaps most) slugs, especially when young, L. marginata is able to suspend itself from a mucus thread secreted by the pedal gland. This thread passes back along the foot to the tip of the tail and adheres to a branch or other object, and supports the animal when it crawls off. Sometimes the slug can even turn around and re-ascend the thread. Kew (1902) gives numerous examples of this process, with details and some figures. Ecology Not uncommon in old and newer woodlands, especially in the west and north. In dry weather it retreats into crevices in the bark and between roots, while in damp weather it crawls up the trunks to a height of twelve feet or more. It is also found on damp rocks on exposed hillsides, and on old stone walls. Distribution (Map 23) Probably occurs in every vice-county of the British Isles, but is commoner in the west and north. In Europe it is found from Iceland and Lapland to Russia and Italy, and is recorded as introduced into Australia and New Zealand. In North America, it apparently occurs wild at Torbay, Newfoundland (confirmed by Altena, 1950). However, introduced slugs from Verdugo Woodlands, Glendale, California, kindly sent by Dr. W. O. Gregg and recorded as this species, proved to be L. poirieri. Probably some of the records from southern Europe also refer to L. poirieri. Material examined Living specimens from the Gower Peninsula and the neighbourhood of Swansea, Glamorgan ; Brecknock ; Caernarvon ; and Torrington, Devon. Spirit material from Britain and Australia. GREENHOUSE ALIENS Lehmannia poirieri (Mabille, 1883) ? Limax valentianus Ferussac, 1823, 2 : g6 e . Limax poirieri Mabille, 1883 : 52. Spain. Notes A full list of references is given by Altena (1950 : 9-17). First British record By Quick (1949 : 24), as L. valentianus. However, Dr. A. D. J. Meeuse had already found it in a greenhouse in Belfast Botanical Gardens, on 26th November, 1948. ig8 BRITISH SLUGS Diagnostic features Somewhat like L. marginata, but the ground colour is yellower and paler, and the body bands nearer to the mid-dorsal line. The radula is like that of Agriolimax, very different from the specialized radula of L. marginata. The penial appendix is longer and more cylindrical than that of L. marginata, and not pointed at the apex. External appearance (PL i, fig. 14) L. poirieri is about 6 cm long, with a yellowish-grey body and mantle, and slightly darker head. The general appearance is watery and translucent, like a pale L. marginata. The keel is short and inconspicuous. A pair of body bands, high up near the mid-dorsal line, are usually more or less interrupted and with scalloped outer edges. Sometimes faint traces of a second pair of bands occur lower down. A pair of mantle bands, becoming broader and darker behind, form a lyre-shaped figure, and the area enclosed is often darker in the centre and mottled with brown. The respiratory orifice is pale bordered. The tripartite sole is uniformly pale. External variation The mantle and body bands vary in width, completeness and the degree of crenu- lation of their outer borders, and there are sometimes faint traces of a second pair of body bands. Jaw Pale yellow, 2-25 mm across. Ra&ula (Text-fig. 17 D) Like that of Agriolimax in having a distinctly tricuspid central tooth, and endo- cones on the lateral teeth a feature which led Pollonera (18870 : 2) to place the species erroneously in that genus. The tri-cuspid central tooth is flanked by fifty-five to sixty teeth on each side, of which about fifteen are typical laterals with endo- and ectocones. Most of the inner marginals are simply aculeate, but many of the outer ones are bifid, while in the extreme outer ones the main cusp becomes multi- denticulate. Alimentary system The intestine shows the two forwardly-directed loops and the long rectal caecum reaching to the apex of the visceral mass, as in L. marginata and Limax flavus. Reproductive system (Text-fig. 17 A) Similar to that of L. marginata, but with the penial appendix longer, and bluntly cylindrical rather than conical. Pollonera (18870) figures the appendix of valentianus as dilated and terminally vesicular, but this may result from misinterpretation of a somewhat folded appendix (Simroth, 1887). Altena (1950) found that Canadian BRITISH SLUGS 199 specimens had simple cylindrical appendices, like those of specimens from Swansea. Another difference from L. marginata is that the sac into which the spermatheca duct expands is somewhat sausage-shaped, rather than pyriform. 15 25 35 JO FIG. 17. Greenhouse aliens. A. Lehmannia poirieri genital organs (x 3-3). B. Limax nyctelius genital organs (x 3-3). G. L. nyctelius penis (x 6-7) opened longitudinally. D. L. poirieri representative radular teeth (x 330). E. L. nyctelius representative radular teeth (x 330). ZOOL. 6, 3. 200 BRITISH SLUGS Mating, development No observations on mating seem to have been recorded. Eggs laid in captivity at Swansea in December 1939 were translucent yellow and measured 2-25 X 1-5 mm. They hatched in February. In March the young measured 10-0 mm long, and had intensely black body and mantle bands, and by loth June they were full grown. Ecology Found always on the ground, never climbing trees and plants like L. marginata. This is true in Tenerife (Altena, 1950) and California (Gregg, in litt.}, and in a green- house at Swansea, where the species was always found under pots. Distribution Spain; the Canary Isles (? introduced) , and introduced into California and Britain (known from greenhouses in Reading, Swansea and Belfast). Material examined Living specimens taken from a greenhouse in Singleton Park, Swansea, Glamorgan, in 1936, 1938 and 1949 ; and from a Reading University greenhouse at Shinfield, Reading, in 1959. Spirit specimens from Verdugo Woodlands, Glendale, California (collected by Dr. W. O. Gregg) ; Guejar de la Sierra, Provincia de Granada, South Spain, and Elizondon, Navarre, North Spain (collected by Dr. de Zarate) and Barcelona. Limax nyctelius Bourguignat, 1861 Limax nyctelius Bourguignat, 1861 : 305, pi. 2, figs. 3 and 4: Algeria. First British record By Quick (1949 : 25). However, A. R. Waterston had found it some years before this, and partially described the species in an unpublished thesis. Diagnostic features Externally like Lehmanniapoirieri, and with a similar radula. Internally resembles L. flavus in having a long rectal caecum, and a long cylindrical penis without an appendix. External appearance L. nyctelius is about 5 cm long, pale greyish-yellow with a thin translucent body- wall. There is a short inconspicuous keel at the hinder end. The mantle bands form a lyre-shaped figure, and the narrow body bands are high up on each side near the mid-dorsal line. The respiratory orifice has a pale border, and the sole is uniformly pale. BRITISH SLUGS 201 External variation The mantle and body bands vary somewhat in breadth and intensity. Like those of Lehmannia poirieri, they tend to fade in alcohol. Jaw Dark brown or blackish, 1-7 mm across. Radula (Text-fig. 17 E) A tri-cuspid median tooth is flanked on each side by thirteen to fifteen tri-cuspid laterals and from twenty-eight to thirty aculeate marginals. The marginals beyond about the nineteenth are bifid, and the extreme marginals trifid. Alimentary system As in L.flavus, with two forwardly-directed loops and a long rectal caecum. Reproductive system (Text-fig. 17 B) The pigmented ovotestis is exposed between the right and left lobes of the liver. The pigmented hermaphrodite duct becomes swollen and folded in its central portion, and ends at the large albumen gland with a pale oval seminal vesicle. The free oviduct is short and stout. The spermatheca arises by a wide duct from the atrium, which expands abruptly to an oval sac which may be pigmented. The penis is uniformly cylindrical, more or less folded, and the vas deferens enters its apex under cover of the stout penial retractor muscle, which arises from the diaphragm close behind the kidney. Internally the penis (Text-fig. 17 c) resembles that of L. flavus in containing a prominent fold starting at the apex and expanding below to a " comb ", and another shorter smooth fold. Ecology Recorded from greenhouses and garden frames in Britain, on date palms in Washington, D.C., and beneath flower pots in Egypt (Abu Teira, in litt.}. Distribution North African coast and Egypt. Introduced into Britain (known from greenhouses in Edinburgh and Glasgow), North America (known from Washington, D.C.) and South Africa (Connolly 1939 : 176). Material examined Spirit specimens from the Royal Botanic Gardens, Edinburgh (sent by A. R. Waterston), Shebin El Kom, Egypt, Algeria and Washington, D.C. 202 BRITISH SLUGS FOSSIL SPECIES Limax modioliformis Sandberger, 1880 Limax modioliformis Sandberger, 1880 : 103, pi. xii, figs. 15-15 c. Fossil shells ascribed to this species are found in the Cromerian at West Runton, Norfolk (Sandberger, 1880). However, the specific ascription of fossil slug shells is at best only tentative. Similar shells in the same beds are ascribed to Lehmannia marginata. FIG. 18. Embryonic vesicles. A. Achatina fulica embryo (x 6-7) showing large caudal vesicle. B. A. fulica later embryo (x 6-7) with vesicle adsorbed. C. TestacMa scutulum embryo (x 6-7) showing cephalic and caudal vesicles. D. Helix aspevsa embryo (x 13) showing caudal vesicle, cephalic vesicle adsorbed. E. Helice-lla itala embryo ( x 20) showing caudal vesicle, cephalic vesicle adsorbed. F. Avion ater embryo (x 17) three weeks after laying, with cephalic and caudal vesicles. G. Agriolimax caruanae embryo ( x 17) with cephalic and caudal vesicles. H. Limax cinereoniger embryo ( x 6-7) with cephalic and caudal vesicles. BRITISH SLUGS 203 ANATOMICAL TERMS The following terms are used throughout this paper, in discussing the genital anatomy of slugs. They are illustrated by somewhat generalized illustrations in Text-fig. 19. The hermaphrodite gonad, far back in the visceral mass, producing ova and spermatozoa. The slender duct conveying ova and spermatozoa from the ovotestis to the albumen gland, oviduct and prostate. A loop, enlargement or diverticulum of the hermaphrodite duct at the albumen gland, for the storage of the animal's spermatozoa. A more or less linguiform gland at the termination of the herma- phrodite duct, supplying the egg albumen. A cavity at the commencement of the oviduct where the ova are fertilized by the partner's spermatozoa. Glandular tubules, opening into the male duct or groove which conveys the spermatozoa. The combined prostate, male duct or groove and oviduct. The prostate usually appears as a yellow ribbon on the gelatinous- looking oviduct. In the Stylommatophora, the proximal parts of the male and female tracts are not completely separate from one another. The slender male duct after it becomes separate and leaves the sperm-oviduct. The female duct, beyond the point where the vas deferens leaves it. The expanded termination of the spermatheca duct, which arises near the termination of the free oviduct (Milax) or directly from the atrium (Arion, Limax and Agriolimax). The spermatheca temporarily stores the partner's spermatozoa. The part of the free oviduct between the origin of the spermatheca duct and the atrium. When the spermatheca duct arises directly from the atrium, there is no vagina. The terminal portion of the genital ducts, receiving the oviduct, penis and often the spermatheca duct. The enlarged terminal portion of the vas deferens, which secretes the spermatophore and leads to the penis. A chitinous capsule containing a mass of spermatozoa (Arion, Milax). The terminal evaginable portion of the male duct, leading to the atrium, and sometimes (Milax) containing a penial papilla. A muscle arising from the body-wall and inserted between the epiphallus (when one is present) and the proximal end or apex of the penis. In Arion a penis and retractor are not present ; the epiphallus enters the atrium direct, and a retractor muscle is inserted on the free oviduct and the spermathecal duct. A slender tubular diverticulum from the apex of the penis (Testacella). A conical or digitiform appendage of the penis (Lehmannia), or a more or less branched appendage at the apex of the penis (Agriolimax). A stimulatory organ situated in the penis (Agriolimax). A stimulatory organ situated in the atrium (Milax) . A lobulated or frilled mass in the atrium or lower part of the oviduct in Arion, which in copula functions as an adhesive organ between the partners. A mass of glandular tubules in Milax, discharging into the termina- tion of the oviduct and the atrium. Ovotestis Hermaphrodite duct Seminal vesicle A Ibumen gland Fertilization sac Prostate Sperm-oviduct Vas deferens Free oviduct Spermatheca Vagina A trium Epiphallus Spermatophore Penis . Retractor penis muscle Flagellum Penial appendix Sarcobelum Stimulator Ligula Vaginal glands BRITISH SLUGS A.Testacella s p UA S P v D FO C. Mi lax vc VD D* Agriolimax S B H D OT S PA FIG. 19. Genital anatomy. A. Testacella. B. Avion. C. Milax. D. Agriolimax. Key : A atrium AG albumen gland E epiphallus F flagellum FO free oviduct FS -fertilization sac HD hermaphrodite duct L ligula LA lower atrium OT ovotestis P penis PA penial appendix PR prostate R retractor muscle SB sarcobelum SP spermatheca SPD spermatheca duct SPO spermoviduct ST stimulator SV seminal vesicle UA upper atrium V vagina VD vas deferens VG vaginal glands. BRITISH SLUGS 205 99SZJSM'Z M^O O O O tww )\O txOO 66 Durham 67 Northumb. S. 68 Cheviotland 69 Westmorland 70 Cumberland 71 Isle of Man % z g a a w s . 3 -g 1 < - g^^^a *& gw -^ oliis ilimtlnv'j2 | i ^ Jl S"0 ^3J*J-g3Sg33.fM ft 1 aS-S'eM'8. Ha S ^ ^SSliS J w 'llllill "i-iillii w "illi 2 M co T^ in'O tN. ooc\OHWfOTj- ino rxoo o\ O H N en TJ- m^o 206 BRITISH SLUGS - pq h .3 (S BRITISH SLUGS 207 S' .S I d 208 BRITISH SLUGS ffl d PQ d _o 4^ a ft c BRITISH SLUGS 209 f 210 BRITISH SLUGS BRITISH SLUGS BRITISH SLUGS 1 5 BRITISH SLUGS 213 2I 4 BRITISH SLUGS BRITISH SLUGS 215 ^=>s! ""# ZOOL. 6, 3. 2l6 BRITISH SLUGS a 'rt -t-> 'iH cc d BRITISH SLUGS REFERENCES ADAMS, L. E. 1898. Observations on the pairing of Limax maximus L. /. Conch, 9 (3) : 92-95 (pi. iii). - 1910. Observations on the pairing of Arion ater (L.). Ibid. 13 (4) : 116-119 (6 text-figs). 1941. Testacella scutulum method of cleansing. Ibid. 21 (8) : 223. ALDER, J. 1848. A Catalogue of the mollusca of Northumberland and Durham. Trans. Tyneside Naturalists' Field Club 1 (2) : 97-209. ALLMAN, G. J. 1843. On a new genus of terrestrial gastropod. Athenaeum (Sept.) : 851, col. 3. 1846. Description of a new genus of pulmonary gasteropods. Ann. Mag. nat. 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Descriptions of some of the species of naked, air-breathing mollusca, inhabiting the United States. Boston Journ. nat. Hist. 4 (2) : 163-175. 1844. On some of the species of naked pneumonobranchus mollusca of the United States. Proc. Boston Soc. nat. Hist. 1 : 51-52. BINNEY, W. G. & BLAND, T. 1869. Land and freshwater shells of North America. Pt. i. Pulmonata Geophila. Smithson. misc. Coll. 8 (3) : i-xii + i-3!6 (545 figs.). BLAND, T. See BINNEY & BLAND, 1869. BONELLI, . In Lessona and Pollonera, 1882. BOUCHARD-CHANTEREAUX, N. R. 1837. Catalogue des mollusques terrestres et fluviatile observes jusqu'a ce jour a 1'etat vivant dans le departement du Pas-de-Calais. Mem. Soc. Agric. Boulogne (n) : 141-230. BOUILLET, J. B. 1835. Catalogue des especes et varietes de mollusques terrestres et fluviatiles observes jusqu'a ce jour a etat vivant, dans la Haute et la Basse- Auvergne, etc. Ann. Scient. Acad. Sci. Clermont-Ferrand 8 : 521-594. BOURGUIGNAT, J. F. i86i. Des Limaces Algeriennes. Rev. Mag. Zool. (2) 13 : 299-306. (Re- printed in Spicileges Malac. pp. 33-43 with new continuation, 2 pp.) BOYCOTT, A. E. 1934. The habitats of land mollusca in Britain. /. Ecol. 22 (i) : 1-38 (i fig.). BREVIERE, L. 1881. Tableau des limaciens des environs de Saint-Saulge (Nievre). /. Con- chyliol. 29 : 306-316. BROECK, E. V. 1870. Excursions decouvertes et observations malacologiques faites en Belgique pendant 1'anee 1870. Ann. Soc. zool. malac. Belg. 5 : 13-64 (pi. 2 ; i text-fig.). CAIN, A. J. & WILLIAMSON, M. H. 1958. Variation and specific limits in the Arion ater aggre- gate. Proc. malac. Soc. Lond. 33 (2) : 72-86 (5 figs.). CHEMIN, E. 1939(2. Observations sur la Testacelle : Testacella europaea Roissy = T. haliotidea Drap. Trav. Sta. zool. Wimereux 13 : 77-85 (pi. 2 ; i fig.). 19396. L'autofecondation chez Testacella europaea Roissy (= T. haliotidea Drap.). C.R. Soc. Biol. Paris 132 (24) : 249-252. ZOOL. 6, 3. i5 2i8 BRITISH SLUGS CLARKE, B. J. 1843. On the species of the genus Limax occurring in Ireland. Ann. Mag. nal. Hist. 12 : 332-342 (3 pis.). In Thompson, 1840. COCKERELL, T. D. A. 1885. The variation and abnormal development of the mollusca. Part 3. Terrestrial Gasteropoda. Hardwicke's Science Gossip 21 (250) : 224-226 (5 figs.). i886a. Notes. The Garner and Science Recorder's Journal 1 (9) : 139. 18866. Notes on some varieties of British shells. /. Conch. 5 (3) : 79-80. i886c. Some varieties of British shells. The Naturalist's World 3 (33) : 179. 18900. The British naturalist's catalogue of the land and freshwater mollusca of the British Islands. The Young Naturalist 11 (127) : 19 pp. 18906. Notes on slugs, chiefly in the collection of the British Museum. Ann. Mag. nat. Hist. (6) 6 : 277-288. 1891. Notes on slugs, chiefly in the collection of the British Museum. Ibid. (6) 7 : 328-341. 1892. A revised list of the species of British Slugs. /. Conch. 7 (3) : 66-70. COLLINGE, W. E. 18920. Descriptions of a new variety of Arion hortensis Fer. and A. circum- scriptus Johnst. The Conchologist 2 (2) : 26-27. 18926. A review of the Arionidae of the British Isles. Ibid. 2 (3) : 56-66. i892c. A review of the Arionidae of the British Isles. Ibid. 2 (4) : 76-83. 1893. On the occurrence of Arion lusitanicus Mab. in the British Isles, and descriptions of four new varieties. Ann. Mag. nat. Hist. (6) 12 : 414-415. 1894. The anatomy and description of a new species of Arion. Ibid. (6) 13 : 66-67 (pi- V.A.). 18950. Amalia parryi, a supposed new species. Journ. Malac. 4 (i) : 7. 18956. Notes on some slugs from Algiers. Proc. malac. Soc. Lond. 1 (7) : 336-337 (pi. xxiii) . 1896. On a collection of slugs from the Sandwich Islands. Ibid. 2 (i) : 46-51 (6 figs.). 18970. Some observations on certain species of Arion. Journ. Malac. 6 (i) : 7-10 (pi. 2). 18976. On some European slugs of the genus Arion. Proc. zool. Soc. Lond. (3) : 439-450 (pis. xxix-xxxi). iSgjc. On a further collection of slugs from the Hawaiian (or Sandwich) Islands. Proc. malac. Soc. Lond. 2 (6) : 293-297 (9 figs.). 1898. Note on a new variety of Testacella maugei Fer. /. Conch. 9 (3) : 95. COMTE, T. LE. 1871. Deuxieme liste supplemental des mollusques terrestres et fluviatiles recueilles aux environs de Lessines. Butt. Soc. mal. Belg. 6 : 6568. CONCHOLOGICAL SOCIETY CENSUS. See Ellis, 1951. CONNOLLY, M. 1939. A monographic survey of South African non-marine mollusca. Ann. S. Afr. Mus. 33 (i) : i-iii + 1-660 (pis. I-XIX ; 58 text-figs.). COOPER, J. G. 1863. On a new genus of terrestrial mollusca inhabiting California. Proc. Calif. Acad. Sci. 3 (i) : 62-63 (* n g-)- DEZALIER D'ARGENVILLE, A. J. 1742. L'Histoire Naturelle eclaircie dans deux de ses parties principales, la lithologie et la conchyliologie . . . viii + 491 pp. (33 pis.) 4to. Paris. D'ORBIGNY, A. D. See Orbigny, A. D. d', 1836-44. DRAPARNAUD, J. P. R. 1801. Tableau des mollusques terrestres et fluviatiles de la France. 116 pp. 8vo. Montpellier & Paris. 1805. Histoire naturelle des mollusques terrestres et fluviatiles de la France, i-viii + 1-164 pp. (13 pis. i port.) 4to. Paris. DROUET, H. 1868. Mollusques terrestres et fluviatiles de la Cote-d'Or. Mem. Acad. Dijon. (2) 14 : 33-154. DRUCE, G. C. 1932. The comital flora of the British Isles, xxxii -f 47 PP- Arbroath. DUMONT, F. 1850. Description d'une espece nouvelle du genre Arion (A. lineatus). Bull. Soc. Hist. nat. Savoie 1 : 64-65. DUMONT, F. & MORTILLET, G. 1856. Catalogue critique et malacostatique des mollusques de Savoie et du bassin du Leman. Bull. Inst. nat. Genevois 4 : 310-361. BRITISH SLUGS 219 ELLIS, A. E. 1926. British Snails. A guide to the non-marine gastropoda of Great Britain and Ireland Pliocene to Recent. 275 pp. (14 pis., n text-figs.). Clarendon Press, Oxford. 1941. The mollusca of a Norfolk Broad. /. Conch. 21 (8) : 224-243. 1951. Census of the distribution of British non-marine mollusca. Ibid. 23 (6 and 7) : 171-244 (8 pp. maps). ESMARK, B. 1883. Nyt Bidrag til Kundekaben om Norges Land og Ferskvands-Mollusker. Nyt. Mag. Naturv. 27 : 77-110. FERUSSAC, J. B. L. D'A. DE. 1819. Histoire naturelle generale et particuliere des mollusques terrestres et fluviatiles 2 : i-xvi + 1-96. Fol. Paris. 1823. Op. cit. (Nouvelle division des pulmones sans opercule) 2 : 96 a- z, a A. FISCHER, P. H. See Gassies & Fischer, 1856. GAIMARD, J. P. See Quoy & Gaimard, 1824. GASSIES, J. B. 1849. Table methodique et descriptif des mollusques terrestres et d'eau douce de I'Argenais. 209 [4] pp. (4 pis. col.). 8vo. Paris. GASSIES, J. B. & FISCHER, P. H. 1856. Monographic du genre Testacelle. Act. Soc. linn. Bordeaux 21 : 195-248 (2 pis.). GERHARDT, U. 1933. Zur Kopulation der Limaciden. Z. Morph. Okol. Tiere 27 (3) : 401-450 (n text-figs.). 1935. Weitere Untersuchungen zur Kopulation der Nacktschnecken. Ibid. 30 (2) : 297-332 (9 figs.). 1939. Neue biologische Untersuchungen an Limaciden. Ibid. 35 (2) : 183-202 (3 figs.). - 1940. Neue biologische Nacktschneckenstudien. Ibid. 36 (4) : 557-580 (8 figs.). GERMAIN, L. 1930. Mollusques terrestres et fluviatiles. Faune Fr. 21 : 447 pp. (13 pis. 470 figs.). GISTEL, J. VON N. F. X. 1848. Naturgeschichte des Thierreichs fur hohere Schulen. xvi + 216 [4] pp. (32 pis. col.). Fol. Stuttgart. (Mollusca pp. 165-174.) GRAY, J. E. 1821. A natural arrangement of mollusca, according to their internal structure. London Medical Repository 15 : 229-239. 1824. On the natural arrangement of the pulmonobranchous mollusca. Annals of Philo- sophy, Land. (N.S.) 24 : 107-109. 1840. A manual of the land and freshwater shells of the British Islands, with figures of each of the kinds. By William Turton (A new edition thoroughly revised and much enlarged by J. E. Gray) ix [i] + 324 pp. (12 pis. col., text illustrated). 8vo. London, i Apr. 1855. Catalogue of Pulmonata or air-breathing mollusca in the collection of the British Museum. Part i. [iv] + 192 pp. (text illustrated). 12 mo. London, 10-18 Apr. GREGG, W. O. 1944. Proterogyny in Deroceras panormitanum. Nautilus 58 : 6768. HAYWARD, J. F. 1954^. Agriolimax caruanae Pollonera as a Holocene fossil. /. Conch. 23 (12) : 403-404 (pi. 15). 19546. A further note on Agriolimax caruanae Pollonera. Ibid. 24 (i) : 21-22. HAZAY, J. 1881, Die Molluskenfauna von Budapest. Malakozool. Bl. (N.S.) 3 : 1-69 (pi. i, figs, i, 2). HELD, F. 1836. Aufzahlung der in Bayern lebenden Mollusken. Isis 29 (4) : 271-282. 1848-49. Die Landmollusken Bayerns. Jahresb. der K. Kreis-Landwirtschafts- und Gewerbs- Schule zu Munchen fur das Schuljahr, 1848-49 : 23. 4to. Miinchen. HESSE, P. 1926. Die Nacktschnecken der palaearktischen Region. Abh. Arch. Molluskenk. 2 (i) : 1-152 (2 pis.). Frankfurt. HEYNEMANN, D. F. 1861. Die nackten Schnecken des Frankfurter Gebiets, vornehmlich aus der Gattung Limax. 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Necrologie : Notice sur le Professor J. A. de Krynicki. Bull. Soc. Imp. Nat. Moscou (i) : 25-33. 1851. Description d'un nouveau genre de limaces de la Russie meridionale. Ibid. 24 : 215-228 (pis. 5, 6). KENNARD, A. S. & WOODWARD, B. B. 1926. Synonymy of the British non-marine mollusca (Recent and Post-tertiary), xxiv -f 447 pp. London. KEW, W. 1902. On the mucous-threads of land-slugs. /. Conch. 10 (5) : 153-165. KOCH, C. & HEYNEMANN, D. F. 1874. Neue Nacktschnecken aus Turkestan. Jb. dtsch. malakol. Ges. 1 : 151-153. KUNKEL, K. 1916. Zur Biologie der Lungenschnecken Ergebnisse vieljdhriger Zuchtungen und Experimente. xvi + 440 pp. (48 text-figs., col. pi.). Heidelberg. LE COMTE, T. See Comte, T. le. LEHMANN, R. 1864. Neue Nacktschnecke aus Australien. Malakozool. Bl. 11 : 145-149. LESSONA, M. 1880. Molluschi viventi del Piemonte. Mem. Accad. Lincei (3) 7 : 317-380 (4 pis.). LESSONA, M. & POLLONERA, C. 1882. Monografia dei Limacidi Italiani. 73 pp. (3 pis.). 4to. Torino (preprint of Mem. R. Accad. Torino (2) 35 : 49-128, 1884). LEYDIG, F. 1876. Die Hautdacke und Schale der Gastropoden, nebst einer Uebersicht der einheimischen Limacinen. Arch. Naturgesch. 42 (i) : 209-292 (pis. ix-xvi). LINNAEUS, C. 1758. Sy sterna Naturae . . . Editio decima, reformata 1 [iv] -f 824 pp. 8vo. Holmiae. 1767. Sy sterna Naturae . . . Editio duodecima reformata 1 (2) : 533-1327. 8vo. Holmiae. LISTER, M. 1674. An extract of a letter of Mr. Martin Lister concerning the first part of his tables of snails, together with some queries relating to those Insecta, and the tables themselves. (Some general queries concerning land and freshwater Snails.) Philosophical Transactions, 9 (105) : 96-99 (pi. 2). 1685-97. Historiae sive synopsis methodicae conchyliorum, etc. 6 pts. Fol. Londini, 1685- 92 (-97)- LOCARD, A. 1895. Ipsa Draparnaudi conchylia. Etude sur la collection conchyliologique de Draparnaud au Musee Imperial et Royal d'Histoire Naturelle de Viennes. 190 pp. Paris. 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(Testacellidae, Arionidae, Limacidae.}. 29 pp. (2 pis. 26 text-figs.). Linnean Society of London. 1950. The spermatophore of Milax sowerbii (Ferussac). /. Conch. 23 (4) : 111-112 (8 figs.). 1952. Rediscovery of Avion lusitanicus Mabille in Britain. Proc. malac. Soc. Lond. 29 (2 and 3) : 93- 101 ( J 5 fi gs.). - 1954. Journey to the Gugh< Highlands (Southern Ethiopia). 1948-49 : Gastropoda, slugs from the high mountains. /. Linn. Soc. (Zool.) 42 : 382-386 (17 figs.). QUOY, J. R. C. & GAIMARD, J. P. 1824. Voyage autour de monde . . . execute sur . . , I'Uranie et la Physicienne . . . Zoologie text. 671 pp. 4to. Paris, 222 BRITISH SLUGS RAFINESQUE-SCHMALTZ, C. S. 1815. Analyse de la nature, etc. 8vo. Palerme. 18200. Annals of Nature or Annual Synopsis of new genera and species of animals, plants etc. discovered in North America . . . First Annual Number, for 1820. i6pp. 8vo. Lex- ington. 18206. Monographic des coquilles bivalves fluviatiles de la Riviere Ohio, etc. Ann. gen. Sci. phys. 5 : 287-322 (3 pis.). RAZOUMOWSKY, G. DE. 1789. Histoire naturelle du Jorat et de ses environs, etc. 1. 8vo. Lausanne. (Mollusca pp. 266-278.) RECLUZ, C. A. 1845. Description des Mollusques terrestres et fluviatiles du Portugal, par A. Morelet. Rev. zool. 1845 : 306-312. Risso, A. 1826. Histoire naturelle des principales productions de I' Europe meridionale, et particulierement de celles des environs de Nice et des Alpes Maritimes. 4. 8vo. Paris. ROEBUCK, W. D. 1883. The British Slug List. /. Conch. 4 (2) : 38-43. 18840. A new variety of Avion ater. Ibid. 4 (5) : 146. i884&. Arion ater var. bicolor in West Gloucestershire. Ibid. 4 (7) : 217. 1885. New varieties of Limax arborum and Arion ater. Ibid. 4 (12) : 375-376. 1921. Census of the distribution of British land and freshwater mollusca. Ibid. 16 (6) : 165-212. ROISSY, A. F. P. M. DE. 1805. Histoire naturelle . . . des Mollusques, etc. (Suites a Hist. Nat. Buffon. redig. Sonnini.) 5 and 6. 8vo. Paris, An. 13. SANDBERGER, C. L. F. VON. 1880. Ein Beitrag zur Kenntnis der unterpleistocanen Schichten Englands. Palaeontographica (N.F. 7) 27 (2) : 83-104 (i pi.). SCHRANK, F. VON P. 1803. Fauna Boica. 8vo. Landshut. (Preface dated 8 Nov., 1802.) SCHRENK, . 1848. Uebersicht der Land und Susswasser Mollusken Livlands. Bull. Soc. imp. Nats. Moscou 21 (i) : 135-185. SCHULTZ, A. W. F. 1836-44. in Philippi, R. A. Enumeratio Molluscorum Siciliae, etc. 2 vols. 4to. Berolini, etc. SIEBERT, H. 1873. Die colorirten Tafeln des Lehmann' schen Werkes. NachrBl. dtsch. malakozool. Ges. (now Arch. Molluskenk.} 5 : 79-82. SIMROTH, H. 1885. Versuch einer Naturgeschichte der Deutschen Nacktschnecken und ihrer Europaischen Verwandten. Z. wiss. Zool. 42 (2) : 203-366 (pis. 7-11). 1887. Einige Bemerkungen, betreffend die Systematik der europaischen Nacktschnecken. NachrBl. dtsch. malakozool. Ges. (now Arch. Molluskenk.} 19 : 161-168. 1906. Ueber eine Reibe von Nacktschnecken die Herr Dr. Cecconi auf Cypern und in Palaestina gesammelt hat. Ibid. 38 (2) : 84-91. SORDELLI, F. 1870. Anatomia del Limax Doriae, Bourg., etc. (Descrizione succinta delle due species di Limax etc.). Atti Soc. ital. Sci. nat. 31 : 242-253 (i pi.). SOWERBY, G. B. 1820. The genera of recent and fossil shells . . . continued by G. B. Sowerby. pt. i. (first issue), pages not numbered. 8vo. London. STOKES, B. M. 1958. The worm-eating slugs Testacella scutulum Sowerby and T. haliotidea Draparnaud in captivity. Proc. malac. Soc. Land. 33 (i) : 11-20. See Barnes & Stokes, 1951. TAYLOR, J. W. 190207. Monograph of the land and freshwater mollusca of the British Isles. (Testacellidae, Limacidae, Arionidae). (pts. 8-13) : i-xx + 1-312 (25 pis. 275 figs, portraits). Leeds. THOMAS, D. C. 1944. Field sampling for slugs. Ann. appl. Biol. 31 (2) : 163-164. THOMPSON, W. 1840. Catalogue of the land and freshwater mollusca of Ireland. Ann. Mag. nat. Hist. 6 : 194-206. TURTON, W. 1831. A manual of the land and freshwater shells of the British Islands, viii + T-5 + [*6] PP- ( IO pl s -> col.). 8vo. London. See Gray, 1840. WATSON, H. 1915. Studies on the carnivorous slugs of South Africa, including a monograph of the genus Apera, and a discussion on the phylogeny of the Aperidae, Testacellidae, and other agnathous Pulmonata, Ann. Natal Mus. 3 (2) : 107-267 (pis. 7-24 ; 7 text figs.). BRITISH SLUGS 223 WATSON, H. 1930. Milax gracilis (Leydig) in the British Isles. Part 2. Anatomy. J . Conch. 19 (3) : 72-93 (pis. i and 2, text-figs. 8-23, map). 1943. Notes on a list of the British non-marine Mollusca. Ibid. 22 (3) : 53-72. See Phillips and Watson, 1930. WEBB & BERTHELOT. See Orbigny, 1836-44. WEIL, J. W. See Barnes & Weil, 1945. WEINLAND, D. F. 1876. Zur Wiechthierfauna der Schwabischen Alb. Jhr. Ver. vaterl. Naturk. Wurttemb. 32 : 234-358 (taf. 4). WESTERLUND, C. A. 1876. Neue Binnenmollusken aus Sibirien. NachrBl. dtsch. malakozool. Ges. (now Arch. Molluskenk.) 8 (8 and 9) : 97-104. WILLIAMS, J. W. 1888. The Shell-collector's handbook for the field, i-xii + 1-148 (14 figs.). 8vo. London. WILLIAMSON, M. H. See Cain & Williamson, 1958. WOLF, J. 1803-06. Die Wurmer. Sturm's Deutschlands Fauna, etc. (Abth. 6. Hft. i and 2). 8vo. WOLLASTON, T. V. 1878. Testacea Atlantica, etc. pp. xi + 588. 8vo. London. WOODWARD, B. B. See Kennard & Woodward, 1926. 224 BRITISH SLUGS INDEX Page agrestis, Agriolimax 163-4, J ^7' 168-70, 178-9 agrestis, Limax . . . 163, 168 Agriolimax 132, 144, 163-80, 181, 194, 198, 203 alba, Arion ater (var.) . . 139 alba, Arion intermedius (var.) . .125 alba, Arion subfuscus (var.) . . 133 alba, Milax sowerbyi (var.) . .158 albida, Arion ater (var.) . . 139 albina, Testacella haliotidea (var.) . 115 albina, Testacella maugei (var.) . . in albolateralis , Arion ater (var.) . .139 aldrovandi, Limax maximus (var.) . 192 allmani, Geomalacus maculosus (var.) . 120 Amalia ..... 149-50 Ambigolimax . . . . .194 andrewsi, Geomalacus maculosus (var.) 120 antiquorum, Limax . . . 187, 191 antiquorum, Limax flavus (var.) . . 184 aperta, Testacella maugei (var.) . . in arborum, Limax . . . .194 Arion . .120, 124-47, 153, 183, 203 Arionidae .... 119-47 Arioninae .... 119-47 ater, Arion 124, 126, 128, 130-31, 133-34, 136-7, 138-47 ater, Arion ater . . . 138-45 ater, Arion ater (var.) . . .139 ater, Limax .... 124, 138 aterrima, Arion ater (var.) . . 139, 145 aurea, Testacella maugei (var.) . . in aurea, Testacella scutulum (var.) . 117 aurigaster, Testacella . . .no babori, Amalia . . . 149-50 benoiti, Milax gagates (var.) . . 151 bettonii, Lehmannia marginata (var.) . 194 bevenoti, Agriolimax . . 172, 175 bicolor, Arion subfuscus (var.) . . 133 bicolor, Milax gagates (var.) . . 151 bilobatus, Limax . . . .170 Binneya . . . . . .119 bisulcata, Testacella . . . .118 breckworthiana, Limax flavus (var.) . 184 brunnea, Arion intermedius (var.) . 125 brunneus, Limax . . . .172 budapestensis, Amalia . . . 160 budapestensis, Milax 149, 155, 158-60, 160-63 caerulea, Arion hortensis (var.) . . 130 campestris, Limax . . . .172 canariensis, Limax . . . .164 Page Candida, Limax maximus (var.) . .192 Carinarion .... 124, 128 carinatus, Limax . . . .158 caruanae, Agriolimax 164,167, 169,173, 175-80 castanea, Arion ater (var.) . . 139 cellaria, Limax maximus (var.) . . 192 cerea, Limax tenellus (var.) . , 181 cereus, Limax . . . .180 cincta, Limax tenellus (var.) . . 181 cineracea, Agriolimax reticulatus (var.) 165 cinerea, Limax cinereoniger (var.) . 188 cinereus, Limax . . . .191 cinereofusca, Arion subfuscus (var.) . 133 cinereoniger, Limax 180, 183, 187-91, 192-3 circumscripta, Arion fasciatas (var.) . 128 circumscriptus, Arion . . .127 coccinea, Arion ater (var.) . . 139 coeruleus, Arion . . . .130 collingei, Amalia . . . .158 concolor, Limax maximus (var.) . .192 cyprius, Agriolimax . . . .164 Deroceras . . . . 163, 179 elongatus, Arion .... 130 empiricorum, Arion . . 124, 138, 145 Endodontacea .... 119-47 Endodontidae . . . . .107 europea, Testacella . . . .115 fasciata, Geomalacus maculosus (var.) . 120 fasciata, Limax maximus (var.) . .192 fasciatus, Arion 124-5, 127-9, 130-4, 144 fasciatus, Limax . . . .127 flavescens, Arion fasciatus (var.) . . 128 flavescens, Testacella haliotidea (var.) . 115 flavogriseus, Arion lusitanicus (var.) . 136 flavus, Arion . . . . .125 flavus, Limax 180, 184-7, 190, 196, 198, 200-1 fuliginea, Arion subfuscus (var.) . 133 fulva, Limax tenellus (var.) . . 181 fulvus, Limax . . . . .180 fuscatus, Arion . . . 133 fuscocarinata, Milax sowerbyi (var.) . 158 gagates, Limax . . . 149-50 gagates, Milax . . 149-55, 156-61 Geomalacus . . . 11924, 137 glauca, Lehmannia marginata (var.) . 194 globosus, Agriolimax . . . .175 gracilis, Limax . . . .160 grisea, Agriolimax laevis (var.) . .173 grisea, Arion fasciatus (var.) . . 138 grisea, Arion hortensis (var.) . .140 griseonigrescens, Testacella maugei (var.) 1 1 1 BRITISH SLUGS 225 Page griseorubescens, Testacella maugei (var.) in gughensis, Agriolimax . . .164 haliotidea, Testacella 108, 109-10, in, 114, 115-6, 117-8 hiberna, Avion ater (var.) . .139 hovtensis, Avion 124, 128-9, 130-2, 133-4, 137. M4 Hydrolimax . . . . .164 hyperboreus, Limax . . . .172 ichnusae, Amalia . . . .156 insularis, Amalia . . . .156 insularis, Milax . . 150, 155, 156-7 intermedia, Limax cinereus (var.) . 187 intermedius, Avion 124, 125-7, 129, 131, 134, 144 Kobeltia . . . . . .124 Krynickillus . . . . .164 lacustris, Agriolimax laevis (var.) . 173 laevis, Agriolimax 164, 167, 172-5, 178-9 laevis, Limax . . . . .172 Lehmannia . . . 193-200, 203 Limacidae .... 147-202 Limacinae .... 163-202 Limacus . . . . .180 Limax . 178, 180-93, 194, 196, 200-2, 203 lineatus, Avion . . . .187 Lochea ..... 124, 133 lusitanicus, Avion 124, 133, 135-8, 144-5 maculata, Agriolimax laevis (var.) . 173 maculata, Amalia . . . .158 maculosus, Geomalacus . 119, 120-4, 137 major, Testacella haliotidea (var.) . 115 marginata, Lehmannia 193, 194-7, 198-200, 202 marginatus, Limax . . . 158, 193-4 marginatus, Milax . . . .149 marginella, Avion ater (var.) . .139 maugei, Testacella . . 109-14, 115-18 maura, Limax cinereoniger (var.) . 188 maurus, Limax . . . .150 maximus, Limax 180, 183, 187-90, 191-3, 197 media, Avion atev (var.) . . .139 meditevranea, Amalia . . .150 megalodontes , Limax . . .184 melitensis, Lehmannia . . 193-4 Mesavion . . . . .124 Microarion . . . . .124 Milax . 149-63, 165, 178, 181, 183, 203 minimus, Avion . . . .125 minutus, Krynickillus . . .164 modiolifovmis , Limax . . . 202 nigva, Agriolimax veticulatus (var.) . 165 nigra, Avion hovtensis (var.) . .130 Page nigva, Testacella maugei (var.) . . in nigrescens, Avion lusitanicus (var.) . 136 nigrescens, Milax sowerbyi (var.) . 158 nigricans, Avion subfuscus (var.) . 133 nigvicans, Parmacella . . .150 nobrei, Avion . . . . 135 normalis, Avion intermedius (var.) . 125 nyctelius, Limax . . 180, 2001 Oleacinacea .... 108-18 Oleacinidae . . . . .107 olivaceus, Avion lusitanicus (var.) . 136 ovetea, Milax sowerbyi (var.) . 158, 160 ovnata, Limax cinereoniger (var.) . 188 pallidus, Limax . . . .170 panormitanus , Derocevas . . .179 panormitanus , Agriolimax . . . 164 Parmacella . . . . .149 Parmacellinae . . . 149-63 parryi, Amalia . . . 14950 pegoravii, Avion subfuscus (var.) . 133 pelhicida, Vitvina . . . .124 perkinsi, Agriolimax . . .175 plumbea, Avion atev (var.) . . .139 plumbea, Avion intermedius (var.) . 125 plumbea, Milax gagates (var.) . . 151 poirieri, Lehmannia . 193-4. 197-200, 201 poirieri, Limax .... 197 punctata, Limax cinereoniger (var.) . 188 vava, Milax gagates (var.) . . .151 veticulata, Agriolimax veticulatus (var.) 165 veticulata, Avion atev (var.) . .139 veticulatus, Agriolimax 163, 164-70, 171-2, 177-9 veticulatus, Limax . . . .164 vosea, Lehmannia marginata (var.) . 194 vufescens, Agriolimax veticulatus (var.) 165 vufescens, Avion hovtensis (var.) . 130 vufescens, Avion lusitanicus (var.) . 136 vufescens, Limax flavus (var.) . 184 vufofusca, Avion subfuscus (var.) . 133 vufus, Avion ater . 138, 139, 144, 145-7 vufus, Limax ..... 145 rupicola, Lehmannia marginata (var.) . 194 vusticus, Milax . . . .149 vutilans, Geomalacus maculosus (var.) . 120 scotti, Agriolimax . . . .164 scutulum, Testacella 108-10, in, 114, 116, 117-8 sevotinus, Limax . . . .180 similis, Amalia mediterranea (var.) . 150 sowerbyi, Limax . . . .158 sowerbyi, Milax . 149-50, 155, 158-60 subflavus, Avion .... 133 226 BRITISH SLUGS Page subfuscus, Arion 124, 129, 133-5, 136-7, 144. 147 subfuscus, Limax . . . 133 subrufa, Lehmannia marginata (var.) . 194 Succinea . . . . . .109 succinea, Arion ater (var.) . . .139 succinea, Arion subfuscus (var.) . 133 sulcatus, Arion . . . .145 sylvatica, Limax maximus (var.) . 192 tenellus, Agriolimax . . . .180 tenellus, Limax 180-4, 185-6, 188, 190 Testacella . . . 108-18, 203 Testacellidae .... 108-18 tetrazona, Limax maximus (var.) . 192 Page tigris, Limax maximus (var.) . . 192 tigrina, Lehmannia marginata (var.) . 194 trigona, Testacella haliotidea (var.) . 115 valentianus, Limax . . . 197-8 variegatus, Limax . . . .184 verkruzeni, Geomalacus maculosus (var.) 120 vinosa, Limax maximus (var.) . .192 violacea, Agriolimax reticulatus (var.) . 165 viridans, Testacella maugei (var.) . in virescens, Limax flavus (var.) . . 184 Vitrina . . . . . .178 Zonitacea .... 147-202 Zonitidae . . . . .107 Zonitoides . . . . .174 i. Geomalacus maculosus. 4. Arion hortensis. 6. Arion intermedius. 9. Arion subfuscus (young). 13 Testacella maugei. PLATE i The scale lines represent one centimetre. 3. Arion ater ater. 7. Arion intermedius (contracted) . 10. Testacella haliotidea. 12. Milax gagates (contracted). 2. Arion subfuscus. 5. Arion fasciatus. 8. Arion fasciatus (contracted). ii. A rion ater rufus (young). 14. Lehmannia poirieri. Bull. B.M. (N.H.) Zoo/. 6, 3 PLATE i PLATE 2 The scale lines represent one centimetre. 15. Agriolimax reticulatus. 16. Limax tenellus. 17. Agriolimax caruanae. 18. Lehmannia marginata. 19. Agriolimax laevis, 20. Milax budapestensis. 21. Lehmannia marginata var. tigrina. 22. Limax flavus. 23. Milax sowerbyi. (contracted) . 24. Limax maximus. 25. Limax cinereoniger. Bull. B.M. (N.H.) ZooL 6, 3 PLATE 2 16 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES (PISCES, CICHLIDAE) PART IV p. GREENWOOD BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) ZOOLOGY Vol. 6 No. 4 LONDON : 1960 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES (PISCES, CICHLIDAE) PART IV BY P. H. GREENWOOD Department of Zoology, British Museum (Natural History) Pp. 227-281 ; 21 Text-figures BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) ZOOLOGY Vol. 6 No. 4 LONDON: 1960 THE BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY), instituted in 1949, is issued in five series corresponding to the Departments of the Museum, and an Historical series. Parts will appear at irregular intervals as they become ready. Volumes will contain about three or four hundred pages, and will not necessarily be completed within one calendar year. This paper is Vol. 6, No. 4 of the Zoological series. Trustees of the British Museum, 1960 PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM Issued March, 1960 Price Twenty Shillings A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES (PISCES, CICHLIDAE) PART IV By P. H. GREENWOOD Department of Zoology, British Museum (Natural History) CONTENTS Page INTRODUCTION ........... 229 Haplochromis lacrimosus (Blgr.) ....... 230 Haplochromis pallidus (Blgr.) ........ 233 Haplochromis macrops (Blgr.) . . . . . . . .236 Haplochromis cinereus (Blgr.) . . . . . . . .239 Haplochromis niloticus nom. nov. ....... 243 Haplochromis martini (Blgr.) . .. . . . . .245 Haplochromis humilior (Blgr.) ........ 248 Haplochromis riponianus (Blgr.) ....... 252 Haplochromis saxicola sp. nov. ....... 256 Haplochromis theliodon sp. nov. ....... 260 Haplochromis empodisma sp. nov. . . . . . . .262 Haplochromis obtusidens Trewavas ....... 266 Haplochromis pharyngomylus Regan . . . . . .270 Haplochromis ishmaeli Blgr. . . . . . . . .275 SUMMARY ............ 280 ACKNOWLEDGMENTS .......... 280 REFERENCES ........... 280 INTRODUCTION IN previous parts of this series I have revised species-groups possessing common or related structural peculiarities and, in most cases, similar feeding habits. The present paper deals with a greater variety of structural and trophic types and many of the species show no obvious relationship to one another. With one exception, the species described below fall into three groups, namely, structurally generalized insectivorous species, specialized mollusc-eaters and species showing various degrees of structural and adaptational intermediacy between the other two groups. The exceptional fish, Haplochromis martini is a piscivorous predator ; it is included simply because of its overall resemblance to one of the insectivorous species described here. Formerly, some of the generalized species reviewed in this paper were synonymized with one of the mollusc-eaters (H. ishmaeli} ; the others are included because of various resemblances to species now resurrected and redefined. One such is Haplo- chromis cinereus, a species previously considered to be the extant representative of the ancestral type from which at least part of the present flock had evolved. These ZOOL. 6, 4 1 6 230 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES views on the central evolutionary position of H. cinereus are no longer tenable since the " species " thought to be H. cinereus was a complex of several distinct species, some more generalized than the others. Haplochromis cinereus, sensu stricto is, in fact, an anatomically somewhat specialized derivative from an even more generalized form. The most outstanding structural character in many of the species described below is an increase in the strength and size of the pharyngeal bones and musculature. As might be expected, these changes are reflected in the diet of the species, which usually include Mollusca as an important element in their food. Two species, H. ishmaeli and H . pharyngomylus , feed almost entirely on snails and bivalves. Those species with the pharyngeal mill in an intermediate stage of hypertrophy are able to deal with small molluscs and also with the tubicolous larvae of certain Trichoptera, an otherwise infrequent element in the food of insectivorous Haplo- chromis without strengthened pharyngeals. By crushing their molluscan prey within the pharynx these species stand in sharp contradistinction to the other groups of mollusc-eating Haplochromis in Lake Victoria. Species in this latter group remove the snail from its shell by holding the foot between the jaws and then levering the soft parts free before ingestion takes place (Greenwood, 19560 and 1957). Haplochromis lacrimosus (Blgr.) 1906 (Text-fig, i) Tilapia lacrimosa (part) Boulenger, 1906, Ann. Mag. nat. Hist. (7) 17, 450 ; Idem, 1907, Fish. Nile, 515 ; Idem, 1915, Cat. Afr. Fish. 3, 234, fig. 154. Haplochromis cinereus (part) Regan, 1922, Proc. zool. Soc. London, 166. Lectotype. An adult male 76 mm. standard length (B.M. [N.H.] 1906.5.30.471) from Entebbe. Description, based on 36 specimens (including the lectotype and 10 paratypes) 66-0-97-0 mm. S.L. Depth of body 31-8-38-7 (M = 35-5) per cent of standard length, length of head 30-8-35-5 (M = 33-5) per cent. Dorsal head profile straight or slightly curved, sloping moderately steeply. Preorbital depth 13-6-18-0 (M = 15-5) per cent of head length, showing weak positive allometry with standard length ; least inter- orbital width 20-8-26-9 (M = 23-5), snout length 26-6-32-2 (M = 29-6) per cent. Diameter of eye 26-1-32-6 (M = 30-4) per cent of head, ratio of eye diameter to preorbital depth 1-5-2-3 (mode 2-0) ; depth of cheek 17-6-23-5 (M 20-8) per cent. Caudal peduncle 15-0-19-2 (M = 17-2) per cent of standard length, 1-2-1-8 (mode 1-5) times as long as deep. Mouth horizontal or almost so ; jaws equal anteriorly, the lower 31-4-41-3 (M = 37-1) per cent of head and 1-2-2-0 (mode 1-6) times as long as broad. Posterior tip of the maxilla extending to the vertical to the anterior orbital margin or slightly beyond, rarely not quite reaching the anterior orbital margin. Gill rakers variable, from moderately stout to slender ; 7-9 (mode 8), rarely 6 on the lower part of the first gill arch, the lowermost two or three reduced. A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 231 Scales ctenoid ; lateral line with 31 (5), 32 (f.2i) or 33 (f.8) scales ; cheek with 2 or 3 (rarely 4) series ; 6 or 7 (rarely 5-|-) between the lateral line and the dorsal fin origin, 7 or 8 (rarely 6) between the pectoral and pelvic fin bases. Scales of the pectoral region small or moderate. Fins. Dorsal with 24 (f.J-9) or 25 (f.i6) rays, anal with n (f.ig), 12 (f.i6) or 13 (f.i), comprising XV-XVI, 8-10 and III, 8-10 spinous and branched rays for the fins respectively. Pectoral 82-5-100-0 (M = 88-5) per cent of head. Caudal truncate or subtruncate. Teeth. The outer row in both jaws is composed of unequally bicuspid, relatively slender and sometimes slightly recurved teeth. Rarely, a few unicuspid teeth may occur anteriorly in this row ; likewise a few posterolateral teeth in the upper jaw FIG. i. Haplochromis lacrimosus ; lectotype (from Boulenger, Fishes of the Nile). may be unicuspid. There are 40-60 (mode 54, modal range 48-54) teeth in the upper jaw. Teeth in the inner series are tricuspid and implanted at a slight, posteriorly directed angle (cf. H. cinereus where the inner teeth lie almost horizontally) ; there are 2 or 3 (rarely 4) rows of inner teeth in the upper jaw and 2 (less commonly 3, rarely 4) in the lower. Lower pharyngeal bone triangular and slender ; a few slightly enlarged but bicuspid teeth may occur in the median tooth-rows. Coloration. The colours of live fishes are unknown. Preserved material : Sexually active males. Ground colour yellowish-silver, chest dusky ; a dark lachrymal stripe is always present and in some specimens it may extend obliquely upwards through the eye and on to the nape ; there are usually two transverse bands across the snout. Two common patterns of body markings are known, (i) A large mid-lateral blotch 232 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES situated slightly posterior to the pelvic fin insertion and a mid-lateral stripe running from a point above the second anal ray on to the caudal fin ; a faint transverse bar is visible immediately posterior to the edge of the operculum and two others lie between the mid-lateral blotch and the origin of the posterior stripe. The blotch itself appears to be the intensified mid-portion of a vertical bar. (ii) Nine, close-set and ventrally ill-defined transverse bars on the flanks ; ventrally, the bars tend to run into one another so that the lower region of the flank is steely- grey. All fins, except the pelvics, hyaline, the upper part of the caudal sometimes weakly maculate, the mid-part dark ; anal with two or three ocelli ; pelvic fins black. Females and quiescent males. Ground colour greyish-silver, brownish above. Seven to nine faint transverse bars on the flanks, not reaching the ventral or dorsal outlines of the body. All fins hyaline. Distribution. At present, H. lacrimosus is known with certainty from Lake Victoria ; Pappenheim & Boulenger (1914) recorded a specimen from Lake Edward, but I have not been able to examine their material. Ecology : Habitat. No precise details are available for fishes already in the col- lections of the B.M. (Nat. Hist.) ; specimens collected by E.A.F.R.O. come from only two localities, both exposed, sandy beaches with the water depth less than 20 feet. Thus, it is impossible to generalize on the habitat preferences of H. lacri- mosus. Food. The stomach and intestinal contents of twenty fishes were examined ; with one exception (a fish from Entebbe) these specimens were caught at one time and at a single locality (Majita, Tanganyika Territory). The gut contents of the sixteen specimens containing food were varied. Twelve fishes contained fine sand- grains, bottom detritus (including fragments of plant epidermis and diatom frustules) and some Cladocera ; five contained remains of insect larvae (probably Diptera), one an adult dipteran, one the remains of a larval Povilla adusta Navas (Ephemerop- tera) and one an insect egg-mass. Two fishes yielded, besides insect fragments, the remains of an oligochaet worm, whilst two others each contained the foot and soft parts of a snail. From these scanty and topographically restricted data, H. lacrimosus should perhaps be classified as a bottom-feeding omnivore. Breeding. The breeding habits are unknown. Two of the smallest fishes (male and female, both 66-0 mm. S.L.) are adult. It seems possible that adult males reach a larger maximum size than do females. Affinities. Haplochromis lacrimosus is one of the structurally and ecologically generalized species of Lake Victoria. Its most striking and apparently diagnostic character is the markings of male fishes ; but, it must be stressed that coloration is known only from preserved material. In general appearance H. lacrimosus resembles H. pallidus (see p. 233) but the two species differ in several characters besides male coloration. A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 233 Study material and distribution records Museum and Reg. No. Locality Collector Uganda B.M. (N.H.). 1906.5.30.471 Entebbe . Degen (Lectotype Tilapia lacrimosa) B.M. (N.H.). 1906.5.30.472-478 . . 1906.5.30.483-484 . Bunjako . ,, 1906.5.30.488-489 . Buganga . 1907.5.7.81-82 . Buddu Coast . Simon 1908.10.19.2-5 . Sesse Islands . Bayon 1959.4.28.24 . Entebbe Harbour . E.A.F.R.O. Tanganyika 1959.4.28.1-23 . Majita Haplochromis pallidus (Blgr.) 1911 (Text-figs. 2 and 3) Tilapia pallida (part) Boulenger, 1911, Ann. Mus. Genova (3), 5, 74; Idem, 1915, Cat. Afr. Fish. 3, 231-2. Labrochromis pallidus Regan, 1920, Ann. Mag. not. Hist. (9), 5, 45 (footnote). Haplochromis cinereus (part), Regan, 1922, Proc. zool. Soc. London, 166. This synonymy is tentative, as I have been unable to locate three specimens of T. pallida which Regan (1922) referred to Haplochromis guiarti (Pellegrin). Regan's genus Labrochromis, based on a skeleton wrongly identified as T. pallida, is discussed on page 275. Description, based on twenty specimens (including the holotype and four para- types) 43-74 mm. S.L. Depth of body 33'3~38-8 (M = 35-4) per cent of standard length, length of head 32-3-35-3 (M 34-1) per cent. Dorsal head profile straight or slightly curved, sloping at about 3O-4O. Preorbital depth 13-2-18-2 (M = 16-5) per cent of head ; least interorbital width 21-0-30-0 (M = 24-7) per cent. Snout as long as broad or slightly longer ; its length 29-1-33-4 (M = 31-2) per cent of head ; diameter of eye 26-1-33-4 (M = 29-5) per cent, ratio of eye diameter to preorbital depth 1-5- 2-3 (mode 1-7) ; depth of cheek 19-0-25-0 (M = 21-7) per cent of head. Caudal peduncle 14-2-18-5 (M = 16-2) per cent of standard length, 1-2-1-7 (mode 1-2) times as long as deep. Mouth horizontal ; jaws equal anteriorly, the lower 32-2-40-9 (M = 37-6) per cent of head and 1-4-1-8 (mode 1-6) times as long as broad. Posterior tip of the maxilla extending to the vertical through the anterior orbital margin or slightly beyond. Gill rakers short and stout (slender in one specimen), 7-9 (mode 9), rarely 10, on the lower part of the first arch, the lowermost 1-4 (or even 5) rakers greatly reduced. Scales ctenoid ; lateral line with 31 (f.6), 32 (1.13) or 33 (f.i) scales ; cheek with 2 or 3 (rarely 4) series ; 6 or 7 (occasionally 5) between the lateral line and the dorsal fin origin, 6 or 7 (occasionally 8) between the pectoral and pelvic fin bases. Scales on the chest rather small. 234 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES Fins. Dorsal with 24 (f-5) or 25 (.15) rays, anal with n (f.3) or 12 (f.i7), com- prising XV-XVI, 8-10 and III, 8 or 9 spinous and branched rays for the fins respec- tively. Caudal truncate ; pectoral fin 78-0-87-0 (M = 81-0) per cent of head. Teeth. The outer row in both jaws is composed of unequally bicuspid, moderately stout teeth implanted erectly. In most fishes more than 67 mm. S.L. some unicuspid teeth occur postero-laterally in the upper jaw. The holotype (the largest specimen examined) has only weakly bicuspid teeth in the outer row. Three small specimens from near the Ripon Falls have somewhat more slender outer teeth than other specimens. There are 36-48 teeth in the upper outer series ; no clear-cut mode can be determined from the sample studied. The small and tricuspid inner teeth are implanted at a very slight angle and arranged in 3 (rarely 2) rows in the upper jaw and 2 or 3 rows in the lower. FIG. 2. Haplochromis pallidus ; holotype (from Boulenger, Ann. Mus. Genova). Lower pharyngeal bone triangular, usually slender but slightly thickened in three specimens. Most fishes have the two median rows of teeth slightly enlarged (especially the most posterior one or two pairs) ; in a few, all the pharyngeal teeth are slender. Coloration. The colours of live fishes are unknown. Preserved material. Adult males. Ground colour greyish, with faint traces of up to seven dark transverse bars on the flank and caudal peduncle ; branchiostegal membrane greyish. A distinct, vertical lachrymal stripe, continued at an angle, runs through the centre of the eye ; a very faint stripe runs from the posterior orbital margin to the angle of the preoperculum. Dorsal fin greyish, with dark lappets and a dark band along the basal two-thirds of the fin anteriorly, narrowing to the basal third or quarter posteriorly. Caudal dark proximally and along the mid-line. Anal hyaline, with two large, dead-white ocelli. Pelvics black, darkest laterally. Females and immature males. Ground colour greyish-silver, six or seven faint transverse bars on the flanks and, in some, two bars on the caudal peduncle ; a very faint lachrymal stripe. All fins hyaline. REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 235 Boulenger's (1911) account of preserved coloration differs somewhat from that given above, but as his material represented at least two and possibly three species, the discrepancies are not considered significant. Distribution. Known only from Lake Victoria, unless the locality " Jinja, Ripon Falls " for specimens nos. 1911.3.3.127-130 implies that these fishes were caught below the falls in the Victoiia Nile. Ecology. Habitat. The only precise bionomic data available are for those specimens collected by E.A.F.R.O. All these were from one locality, an exposed, shallow and sandy beach near Entebbe Airport. Food. Thirteen of the sixteen fishes examined had ingested matter in the stomach and intestine ; all these specimens were collected at one locality and at the same FIG. 3. Haplochromis pallidus; lower pharyngeal bone, oc- clusal view. 0-2 cm FIG. 4. Haplochromis ripon- ianus ; lower pharyngeal bone, occlusal view. FIG. 5. Haplochromis saxi- cola ; lower pharyngeal bone, occlusal view. time. Except for three fishes, all contained moderately large quantities of bottom debris (sand grains, diatom frustules and fragments of plant tissue) together with fragmentary insect larvae (? Diptera). The exceptional specimens contained only bottom detritus. Breeding. Haplochromis pallidus is a female mouth brooder ; the two smallest fishes examined (a male 54 mm. S.L. and a female 58 mm. S.L.) are both adult. Affinities. Haplochromis pallidus must be considered one of the many small and generalized species in Lake Victoria. Within this group it is extremely difficult to suggest phyletic relationships because the degree of inter-specific differentiation is so slight. In general appearance H. pallidus perhaps comes nearest to H. lacrimosus, from which species it is distinguished by a higher modal number of gill rakers (9 cf. 8), fewer and somewhat stouter teeth, a lower modal eye/preorbital ratio (1-7 cf. 2-0) and particularly, by differences in the preserved coloration of male 236 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES fishes. The nature of both oral and pharyngeal dentition suggests that a " pallidus " like species could have been ancestral to the adaptational grade at present represented by Haplochromis humilior (see p. 252). Study material and distribution records Museum and Reg. No. Locality Collector Uganda Genoa Museum (C.E. 12912) . Jmja . Bayon B.M. (N.H.). 1911.3.3.127-130 . Jinja, Ripon Falls . 1959.4.28.25-40 . Entebbe, Airport beach .. E.A.F.R.O. Haplochromis macrops (Blgr.) 1911 (Text-fig. 6) Haplochromis stanleyi (part) Boulenger, 1914, Cat. Afr. Fish. 3, 295. Haplochromis ishmaeli (part) Boulenger, 1914, torn. cit. 293. Tilapia macrops Boulenger, 1911, Ann. Mus. Geneva (3), 5, 73. pi. Ill, fig. i ; Idem, 1914, Cat. Afr. Fish. 3, 238. Haplochromis macrops (part, i.e. the species as described but excluding the tentative synonymy of Astatotilapia jeanneli Pellegrin), Regan, 1922, Proc. zool. Soc. London, 166. Description, based on forty specimens from Lake Victoria (including the holotype [Genoa Museum] and one of the paratypes) 66-91 mm. S.L. Depth of body 32-5-38-2 (M = 35-8) per cent of standard length, length of head 31-0-35-1 (M = 33-0) per cent. Dorsal head profile straight or slightly curved, sloping at a moderate angle (ca. 35-4O). Preorbital depth 11-5-16-3 (M = 14-2) per cent of head, least width of interorbital 26-6-32-2 (M = 29-7) per cent. Snout as broad as long or slightly broader, its length 26-6-31-0 (M = 29-0) per cent of head, diameter of eye 28-6-35-4 (M = 33'o) per cent, ratio of eye diameter to pre- orbital depth 2-0-2-9 (mode 2-3) ; depth of cheek 17-8-24-2 (M = 21-1) per cent of head. Caudal peduncle 14-1-18-4 (M = 16-8) per cent of standard length, 1-2-1-6 (mode 1-4) times as long as deep. Mouth slightly oblique, posterior tip of the maxilla extending to the vertical to the anterior orbital margin or even as far as the pupil. Lower jaw 38-0-42-5 (M = 39-5) per cent of head, 1-4-2-2 (modal range 1-7-1-8) times as long as broad. Gill rakers slender or, occasionally, relatively stout ; 8-n (mode 9) on the lower part of the first arch, the lower 1-4 rakers reduced. Scales ctenoid; lateral line with 30 (f.6), 31 (f.i7), 32 (f.i3) or 33 (f.3) scales; cheek with 2 or 3 series. Five or 6 (occasionally 7) scales between the lateral line and the dorsal fin origin ; 6 or 7 (occasionally 5, rarely 8) between the pectoral and pelvic fin bases. Scales on the pectoral region (relative to those on the ventral abdominal region) moderate to large. Fins. Dorsal with 24 (f.6), 25 (f-3o) or 26 (f.4) rays, anal with u (f-9), 12 (1.30) or 13 (f.i), comprising XV-XVII, 8-10 and III, 8-10 spinous and branched rays for the fins respectively. Pectoral 68-0-96-0 (M = 84-0) per cent of head. Caudal truncate. A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 237 Teeth. The outer row of teeth in both jaws (except those situated postero-laterally in the upper) is composed mainly of bicuspid, moderately stout teeth. In certain fishes over 80 mm. S.L. some weakly cuspidate teeth may occur. H. macrops is, however, unusual in that the postero-lateral teeth in the upper jaw are generally tricuspid in fishes less than 85 mm. S.L. ; in larger individuals these teeth may be unicuspid. One aberrant individual has only tricuspid teeth in the upper, outer row ; the corresponding row in the lower jaw has a mixture of bi- and tricuspids, with the former predominating. There are 46-66 (mode 60, modal range 56-60) teeth in the upper, outer row. The inner tooth-rows are made up of tri- and unicuspid teeth arranged in 2 or 3 (rarely 4) rows in the upper jaw and I or 2 (less commonly 3) rows in the lower. Inner teeth are implanted so as to stand erect or with a very slight, posteriorly directed slope. FIG. 6. Haplochromis macrops ; holotype (from Boulenger, Ann. Mus. Genova). Lower pharyngeal bone triangular, not enlarged ; teeth fine and cuspidate. Coloration in life. Sexually active males. Ground colour dusky to intensely black. Dorsal fin black, lappets and margin of the soft part red, as are the spots and blotches between the branched rays. Anal dusky with a diffuse red flush becoming more intense distally : ocelli yellow. Caudal dusky, ventral half with a red flush. Pelvic fins dusky yellow. Quiescent males have a female-type coloration, but with yellow anal ocelli and red spots on the soft dorsal. Females. Ground colour greyish-yellow to silver-grey. Dorsal and anal fins light yellow, caudal yellowish. Colour of preserved material. Adult males. Dark blackish-brown, somewhat lighter, except in sexually active fishes, on the chest and branchiostegal membrane ; faint indications of six transverse bars on the flanks (generally not reaching the dorsal and ventral outlines) ; a dark but faint lachrymal stripe is visible in some specimens, 238 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES as is a faint dark bar along the preoperculum. Dorsal fin dark (especially along the basal third), lappets black. Caudal fin dark. Anal dark on the basal third to half, pale distally, with two or three ocelli. Pelvic fins black. Females. Brownish-yellow, some with eight or nine faint transverse bars on the flank and caudal peduncle. All fins hyaline but the caudal somewhat darker. Distribution. Definite records of Haplochromis macrops are available only from Lake Victoria although there is an indication that the species may also occur in the Lake Edward basin. I have examined material identified as H. macrops from Lake Edward (one specimen B.M. (N.H.) Reg. No. 1933.2.23.397 ; see Trewavas, 1933) and from rivers flowing into Lake Edward (see Poll, 1939 and Poll & Damas, 1939). Of these latter specimens (twelve in all) only one (R. G. Mus. Congo 31095, det. David, 1936), from Rutshuru, compares closely with the Victoria population of H. macrops. I hesitate to identify the remaining Congo Museum specimens from Rutshuru (Reg. Nos. 64888-64899), but the single specimen from the B.M. (N.H.) seems most closely allied to H. lividus Greenwood of Lake Victoria. I have not been able to study the two specimens from Lake Edward (now in Berlin) which Pappen- heim & Boulenger (1914) identified as H. macrops. The single specimen (R. G. Mus. Congo 31095) from the Edward basin now referred to H. macrops differs slightly from the generality of Victoria fishes in having a somewhat larger eye and longer lower jaw ; it is an adult female, 73-0 mm. S.L. The principal morphometric characters of this fish are : D* H* Po.% Io.% Eye% Snt. % Ck. % Lj. % C.R* Eye/Po. 32-8 31-4 15-2 30-4 37-0 30-4 21-7 43-4 15-0 2-4 * Per cent standard length. % Per cent head length. Dorsal XV, 9 ; anal III, 9 ; pectoral 91-3 per cent of head. In characters of dentition and squamation this fish is similar to those from Lake Victoria. Ecology. Habitat. The species is apparently confined to the shallow, sandy regions of the lake. Food. The predominating food organisms in the stomachs and intestines of twenty-four fishes (mainly from one locality, but caught on different occasions) are sub-imaginal Ephemeroptera ; two fishes had, however, fed almost exclusively on winged termites (Isoptera) and colonial blue-green algae. Typical bottom debris and sand-grains usually found in the guts of other insectivorous Haplochromis were not recorded. The occurrence of sub-imaginal or adult insects and planktonic blue- green algae, together with the absence of bottom debris, suggests that H. macrops feeds at the surface or in mid-water. Since the algae were not digested and did not constitute a major proportion of the ingested matter, they may be taken accidentally as the fishes dart after insect prey. Breeding. Haplochromis macrops is a female mouth-brooder. The smallest sexually active fish is a female 73 mm. S.L., the smallest adult male is 78 mm. S.L. It appears that males attain a larger maximum adult size than do females. A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 239 Affinities. As with most of the structurally and trophically generalized Haplo- chromis of Lake Victoria, the detailed affinities of H. macrops are impossible to determine. The similarities existing between H . macrops and H. cinereus are discussed elsewhere (p. 242). The two species differ in several characters, particularly in their dentition and the larger eye/preorbital ratio of H. macrops (2-0-2-9, mode 2-3, cf. i '5-1-9, mode 1-8 for H. cinereus). Also, the gill rakers of H. macrops are finer and more numerous (mode 9) than in H. cinereus (mode 7). The large eye and shallow preorbital of H. macrops serve to distinguish the species from most other members of the " generalized species " group. Study material and distribution records Museum and Reg. No. Locality Collector Uganda Genoa Museum (C.E. 12928) . Bussu . Bayon (Holotype) B.M. (N.H.). 1911.3.3.137 . Bussu . Bayon (Paratype) B.M. (N.H.). 1911.3.3.114-115 . Jinja, Ripon Falls 1959.4.28.51-78 . Beach near Nasu Point . E.A.F.R.O. ,, 1959.4.28.79-84 . Buka Bay . ,, Tanganyika ,, 1959.4.28.85 . Mwanza, Capri Bay . ,, 1959.4.28.86 . Majita . ,, 1959.4.28.87 . Beach near Majita . ,, Haplochromis cinereus (Blgr.) 1906 (Text-fig. 7) Paratilapia cinerea Boulenger, 1906, Ann. Mag. nat. Hist. (7), 17, 439 ; Idem, 1907, Fish. Nile, 478 ; Idem, 1915, Cat. Afr. Fish. 3, 344. Haplochromis stanleyi (part), Boulenger, 1915, torn, cit., 295. Tilapia lacrimosa (part) Boulenger, 1906, Ann. Mag. nat. Hist. (7), 17, 450 ; Idem, 1915, torn. cit., 234. Haplochromis cinereus (part), Regan, 1922, Proc. zool. Soc. London, 166. Haplochromis melanopus (part), Regan, 1922, op. cit. 165. Description, based on twelve specimens (including the holotype) 71-81 mm. S.L. Depth of body 34-6-39-0 per cent of standard length, length of head 30-8-37-3 (M = 34-7) per cent. Dorsal head profile straight or slightly curved, sloping at ca. 4o-5o. Preorbital depth 15-0-18-0 (M = 16-4) per cent of head length, least interorbital width 23-3-28-0 (M = 25-3) per cent. Snout as long as broad or slightly longer, its length 29-2-34-6 (M = 32-2) per cent of head, eye diameter 26-2-32-0 (M = 28-7) per cent, ratio of eye diameter to preorbital depth 1-5-1-9 (mode 1-8). Depth of cheek 20-8-26-0 (M = 23-0) per cent of head. Caudal peduncle 15-7-18-7 per cent of standard length, 1-4-1-6 times as long as deep. 240 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES Mouth horizontal or very slightly oblique ; jaws equal anteriorly, the lower 34-6-41-3 (M = 37-7) per cent of head and 1-4-1-8 (mode 1-6) times as long as broad. Lips slightly thickened. Posterior tip of the maxilla extending almost to the vertical through the anterior orbital margin or as far as the eye. Gill rakers moderately stout, 7-9 (mode 7) on the lower part of the first gill-arch, the lowermost two or three rakers reduced. Scales ctenoid ; lateral line with 30 (f.i), 31 (f.i), 32 (f.4) or 33 (f.6) scales ; cheek with 3 or 4 series ; 5~6| scales between the lateral line and the dorsal fin origin ; 7 or 8 (rarely 6 or 9) between the pectoral and pelvic fin bases. Scales on the pectoral region small or, less frequently, moderate. Fins. Dorsal with 24 (f.8) or 25 (f.4) rays, anal with n (f.4) or 12 (f.8), comprising XV or XVI, 9 or 10 and III,' 8 or 9 spinous and branched rays for the fins respectively. Caudal truncate. Pectoral 72-5-92-0 (M = 80-2) per cent of head. FIG. 7. Haplochromis cinereus ; holotype (from Boulenger, Fishes of the Nile). Teeth. Teeth in the outer row of both jaws are weakly bicuspid or unicuspid, relatively stout and slightly recurved ; in most fishes there is an admixture of both types, with unicuspids predominating. There are 40-54 teeth in the upper, outer row. The inner series are composed of either unicuspid or bicuspid teeth ; less commonly there is a mixture of both types. A characteristic feature of the inner tooth-rows is the way in which the teeth are implanted obliquely so that the crowns point posteriorly. Three or 4 (rarely 2) inner rows occur in the upper jaw and 2 or 3 in the lower. The dentition of H. cinereus is unlike that of other species in the " generalized species ' ' group ; it is, indeed, typical of the dentition found throughout the large group of piscivorous predators. However, in other characters (syncranial architec- ture, feeding habits and body-form) H. cinereus is one of the generalized species (see p. 242). A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 241 Lower pharyngeal bone triangular, the dentigerous surface slightly broader than long. Teeth in the two median rows are slightly enlarged in five of the specimens examined, but are slender in the remaining seven fishes ; the other pharyngeal teeth are slender in all specimens. Coloration in life unknown. Colour of preserved fishes : Adult males. Ground colour greyish-brown ; chest and branchiostegal membrane dusky ; a faint lachrymal stripe. All fins hyaline, with very faint indications of dark maculae on the soft dorsal ; dorsal lappets dark. Anal fin with two or three whitish ocelli (orange surrounded by red in newly preserved material, according to Boulenger). Pelvics black except for a large light area extending over the distal half but not including the first branched ray. Females. Brownish, silvery grey ventrally, with eight or nine dark transverse bars on the flanks and caudal peduncle. All fins hyaline, the basal third to half of the caudal weakly maculate. Distribution. Known only from Lake Victoria. Ecology. No ecological data (except the locality) are available for the three specimens collected by Degen. The remaining nine fishes were caught in water less than 20 feet deep, over a sandy bottom on both protected and exposed shores. Food. The stomach and intestinal contents of ten specimens (from four localities) were examined. Of these, three were empty and the remainder yielded sand-grains, bottom detritus (including fragments of plant epidermis) and some larvae of dipterous insects. Breeding. The species is a female mouth-brooder. The smallest specimens available (a male and a female 71 mm. S.L.) are both sexually mature. As far as can be determined from this inadequate sample, both sexes reach the same adult size. Discussion of affinities and synonymy. In Regan's revision of the Lake Victoria Haplochromis (1922) the definition of H. cinereus was expanded to embrace a number of small and generalized or near-generalized forms previously recognized as distinct species. The first attempt to prune this complex was Lohberger's resurrection of H riponianus (see p. 252). Now, with more specimens available and some knowledge of Haplochromis in nature, it is clear that Regan's definition of H. cinereus must be narrowed considerably and that a further two species (H. lacrimosus and H. pallidus] should be resurrected. Amongst the group of anatomically and trophically un- specialized Haplochromis in Lake Victoria, H . cinereus is unusual because of its oral dentition (see p. 240). Relatively stout, clearly bicuspid teeth in the outer series of the jaws and erect tricuspid inner teeth are usual in the generalized species. The dentition of H. cinereus, on the other hand, shows a marked tendency for slender, unicuspid teeth to predominate in the outer rows ; the few bicuspid teeth present are weakly cuspidate. The inner teeth of H. cinereus are also atypical for the group in that the usual erect and tricuspid form is largely replaced by slender unicuspids implanted so as to point posteriorly. In fact, the dentition of H. cinereus is very like that of many predatory species. With so few specimens of H . cinereus known it is impossible to generalize on its feeding habits ; however, the gut contents of 242 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES seven fishes from four different localities do not even hint at the species being a piscivorous predator. At this point it should perhaps be stressed that my observations are confined to adult fishes 70-90 mm. long ; juveniles have still to be discovered. Because " Haplochromis cinereus " had become something of a dumping ground for any small Haplochromis species or specimen, the published information (Graham, 1929) on distribution and habitats can no longer be considered reliable. I have examined " H. cinereus " material collected by Graham and find that none of these specimens is referable to H. cinereus, sensu stricto. The bulk of this material is of undescribed species and will be dealt with in subsequent papers. Thus, Graham's remark that " the species (H. cinereus) is therefore widely distributed except in the deepest part of the lake " and Brooks' (1950, p. 159) elaboration of these data do not apply to H. cinereus but rather to the whole species-complex of generalized, bottom feeding Haplochromis in the lake. Haplochromis cinereus has been cited as representing the ancestral type from which the present species-flock could have evolved (Regan, 1922 ; Greenwood, 1951). For the reasons mentioned above this concept must be abandoned ; there are several other Haplochromis species still surviving in Lake Victoria which are structurally closer to the ancestral type, for example H. lacrimosus, H. nubilus or H. pallidus. The particular affinities of H. cinereus are difficult to determine. In gross anatomy and appearance H. cinereus does not differ markedly from the majority of small Haplochromis ; only when its dentition is considered does the difference appear striking. Like so many members of the generalized group, H. cinereus seems to be an independent offshoot from one of the basic stocks. In overall appearance and perhaps in at least some ecological requirements Haplochromis macrops is the one extant species most like H. cinereus. The two species are differentiated principally by the larger eye, shallower preorbital and the stouter, more numerous outer teeth of H. macrops. Haplochromis cinereus is not, as Regan suggested, closely related to H. ishmaeli. To stress this supposed relationship, Regan noted that six of the H. ishmaeli syntypes were actually specimens of H. cinereus. As a result of this present revision none of these specimens is still retained in H. cinereus. Haplochromis ishmaeli belongs to a distinct phyletic line, discussed more fully on pages 269 and 273. Study material and distribution records Museum and Reg. No. Locality Collector Uganda B.M. (N.H.). 1906.5.30.292 . Buganga . Degen (Holotype) B.M. (N.H.). 1906.5.30.350 . Entebbe . ,, 1906.5.30.482 . Bunjako ,, 1959.4.28.41 . Entebbe, Harbour . E.A.F.R.O. ,, 1959.4.28.48-50 . Entebbe, Airport beach . ,, Tanganyika ,, 1959.4.28.42-47 . Mwanza, Capri Bay . E.A.F.R.O. A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 243 Haplochromis niloticus nom. nov. (Text-fig. 8) Tilapia bayoni Boulenger, 1911, Ann. Mus. Genova (3), 5; 72, pi. Ill, fig. 2 (nee Paratilapia bayoni [ = Haplochromis bayoni (Blgr.), see Regan, 1922, p. 176] Blgr., 1909, Ann. Mus. Genova (3), 4, 304, fig. Haplochromis humilior (part), Regan, 1922, Proc. zool. Soc. London, 169. Description, based on the holotype (100 mm. S.L.) and two other specimens 96 and 102 mm. S.L. FIG. 8. Haplochromis niloticus ; holotype (from Boulenger, Ann. Mus. Genova). The principal morphometric characters are given below : S.L. Depth* Head* Po. % lo. % Snt. % Eye % Ck. % T i / **J /o C.P.* 96-0 35'4 33-3 17-2 21-8 31-3 31-3 20-4 39'0 18-2 fioo-o 33' 33' 15-2 24-3 30-3 33'5 24-0 33'3 I7-5 IO2 -0 34-3 33-8 17-4 24-7 29-0 30-5 23-2 37'7 17-1 f Holotype. % Per cent, of head length. * Per cent, of standard length. Dorsal head profile sloping rather steeply (ca. 45-5o) and slightly curved. Mouth horizontal ; jaws equal anteriorly, the length /breadth ratio of the lower i-6-i-g. Posterior tip of the maxilla extending to the vertical through the anterior part of the eye. Lips not markedly thickened. ZOOL. 6, 4 17 244 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES Gill rakers moderately stout ; 7 or 8 (the lowermost one or two reduced) on the lower part of the first arch. Scales ctenoid ; 32 in the lateral line ; cheek with 2 or 3 series. Six or 7 scales between the lateral line and the dorsal fin origin, 8 or 9 between the pectoral and pelvic fin bases ; scales on the pectoral region small. Fins. Dorsal with 25 (f.2) or 26 (f.i) rays, anal with 12, comprising XVI, 9-10 and III, 9 spinous and branched rays for the fins respectively. Pelvic fins with the first branched ray only slightly produced and extending to the origin of the anal. Caudal sub-truncate, scaled only on its proximal half. Teeth. The outer row in both jaws is composed of moderately slender, movably implanted and unequally bicuspid teeth ; the most posterior five or six teeth in the upper jaw are caniniform and stouter than those situated anteriorly and laterally. There are 65-70 teeth in the upper, outer series. Teeth in the inner series are small and tricuspid, and are arranged in four or five rows in the upper jaw and four in the lower. The interspace between the inner and outer series is very narrow. Lower pharyngeal bone triangular, slender or slightly enlarged, the two median rows of teeth relatively coarse in two specimens (including the holotype) and some- what more enlarged in the third. In the latter fish the next lateral row of teeth is also enlarged and the most posterior teeth of the median rows are sub-molariform. Osteology. A complete skeleton was prepared from one of the specimens caught at the same time as the three fishes described above. However, since H. niloticus is very similar to H. nuchisquamulatus (which also occurs in the Victoria Nile) it is difficult to confirm the specific identity of the skeleton. Apparently the sole diag- nostic osteological character is the lower pharyngeal bone, which is slender in H. nuchisquamulatus and slightly thickened in H. niloticus. The lower pharyngeal of the skeleton is that of H . niloticus and on this character alone the skeleton is referred to H. niloticus. In all other characters, except the oral dentition, the skeleton of H. niloticus resembles that of a generalized Haplochromis species. There are 14 + 16 vertebrae. Coloration of live fishes is unknown. The three preserved specimens are all ap- parently males (judging from the well-defined anal ocelli) and adult. Because most of the coloration is now lost (the fishes are a uniform brownish-grey) I quote the description given by Boulenger (1911) of the then newly preserved specimens. " Back dark olive to blackish, sides brassy yellow to coppery red ; a more or less distinct black bar below the eye ; dorsal and ventrals brown to black ; anal pink, blackish at the base, usually with two or three large orange ocellar spots ; caudal brown or blackish the lower third often pink." From this description the coloration of male fishes seems to be remarkably like that of H. humilior from Lake Victoria (see p. 250). Distribution. Haplochromis niloticus is known only from the Victoria Nile ; no information is available on its habitat or on feeding and breeding habits. Affinities. Haplochromis niloticus has been compared with two Haplochromis species from Lake Victoria. In his original description, Boulenger compared the A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 245 species with H. martini, whilst Regan (1922) considered H. niloticus to be conspecific with H. humilior. In my opinion H. martini and H. humilior are not closely related to one another and H. niloticus is not allied to either. The three species differ in several fundamental characters, especially in the nature of their dentition. Ad- mittedly, the somewhat enlarged median pharyngeal teeth of H. niloticus approach the condition found in some specimens of H. humilior, but the oral dentition of the two species is very dissimilar. The outer teeth are finer and more numerous in H. niloticus and there are more rows of inner teeth barely separated from the outer row. These same characters, together with a somewhat different arrangement of the jaw skeleton, serve to separate H. niloticus from H. martini. The nature of the dentition in H. niloticus suggests affinity with H. nigricans and H. nuchisquamulatus, particularly the latter. From H. nigricans, H. niloticus is distinguished by its more generalized neurocranium and dentary (see Greenwood, 19566) and its slightly enlarged lower pharyngeal teeth. From H. nuchisquamulatus, H. niloticus is again distinguished by having somewhat enlarged pharyngeal teeth and by a narrower interorbital region. The affinities of H. niloticus are not especially obvious ; the species is probably yet another slightly specialized side branch from the generalized Haplochromis stem. Study material and distribution records Museum and Reg. No. Locality . Collector Uganda Genoa Museum (C.E. 12932) . Kakindu, Victoria Nile . Bayon (Holotype T. bayoni Blgr. 1911) B.M. (N.H.) . 1911.3.3.124-5 . 1911.3.3.126 . (skeleton) Haplochromis martini (Blgr.) 1906 (Text-fig. 9) Tilapia martini, Boulenger, 1906, Ann. Mag. nat. Hist. (7), 17, 449. T. martini (part), Idem, 1914, Cat. Afr. Fish. 3, 239, fig. 158. Haplochromis martini, Regan, 1922, Proc. zool. Soc. London, 171. Regan (1922) based his redescription of H. martini on three of the six syntypes, but did not indicate to what species he referred the remaining type specimens. However, amongst the material Regan identified as H. cinereus there are three type specimens of T. martini (B.M. (N.H.) Reg. No. 1906.5.30.466-468). Presum- ably it was Regan's intention to include these in the published synonymy of H. cinereus. The three specimens are not H. cinereus but are, in fact, Haplochromis martini. Lectotype. A brooding female 88 mm. standard length (B.M. (N.H.) Reg. No. 1906.5.30.465) from Bunjako, Uganda. Description, based on twenty-nine specimens (including the lectotype and four paratypes) 59-104 mm. S.L. 246 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES Depth of body 30-8-38-0 (M = 34-4) per cent of standard length, length of head 31-0-38-1 (M = 35-4) per cent. Dorsal head profile very strongly decurved, the snout sloping at an angle of ca. $o-yo. Depth of preorbital 13-0-20-0 (M = 16-6) per cent of head, least interorbital width 20-4-26-8 (M = 24-1) per cent. Snout slightly longer than broad, its length 27-3-34-4 (M 30-2) per cent of head ; dia- meter of eye 29-4-37-5 (M = 31-7) per cent, depth of cheek 20-4-27-7 (M = 24-6) per cent. Caudal peduncle 15-3-20-6 (M = 17-3) per cent of standard length, 1-2-1-8 (mode 1-6) times as long as deep. Jaws equal anteriorly, the lower 38-4-45-8 (M = 42-6) per cent of head, 1-6-2-1 (modal range 1-7-2-0) times as long as broad ; mouth horizontal or slightly oblique. Posterior tip of the maxilla extending to the vertical through the pupil or, less commonly, only to the anterior part of the eye. Such a marked posterior extension of the maxilla is unusual in Lake Victoria Haplochromis and may be considered one of the diagnostic characters of H. martini. FIG. 9. Haplochromis martini ; lectotype (from Boulenger, Fishes of the Nile). Gill rakers on the first arch moderately stout (but rather slender in a few specimens), one or two of the uppermost often flattened and bifid ; 8 or 9, rarely 7 or 10 (mode 9) gill rakers on the lower part of the arch. Scales ctenoid; lateral line with 31 (.5), 32 (f-7), 33 (.9), 34 (.7) or 35 (f.i) scales ; cheek with 3 or 4 rows. Six to 8 scales between the lateral line and the dorsal fin origin, 7 or 8 (rarely 6) between the pectoral and pelvic fin bases. Fins. Dorsal with 24 (1.9), 25 (f.ig) or 26 (f.i) rays, anal with n (f.8), 12 (f.i-9) or 13 (f.2), comprising XIV-XVI, 8-10 and III, 8-10 spinous and branched rays for the fins respectively. Pectoral fin 73'5-865 (M = 82-0) per cent of head ; caudal truncate or sub-truncate. Teeth. In the outer row of both jaws the teeth are slender and mainly unequally bicuspid in fishes less than 85 mm. S.L. Above this size both weakly bicuspid and unicuspid teeth occur together. In fishes of all sizes a few tricuspid teeth are found postero-laterally in the upper jaw, an uncommon character in Lake Victoria Haplo- chromis (see H. macrops, p. 237). There are 46-76 teeth in the upper jaw (ill-defined modal range 68-70). A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 247 Tricuspid teeth predominate in the inner series although in one large fish (101 mm. S.L.) the inner teeth are all unicuspid. The inner series are arranged in 2 (less commonly 3) rows in the upper jaw and in i or 2 (less commonly 3) rows in the lower. Lower pharyngeal bone triangular, not enlarged and with slender, cuspidate teeth. Osteology. The neurocranium does not differ greatly from the generalized Haplo- chromis type, but the premaxilla has relatively longer dentigerous arms. Coloration in life. Sexually active males. Ground colour golden-yellow, shading to silvery- white, with three or four faint black blotches below the insertion of the dorsal fin, and a distinct coppery sheen on the nape and anterior part of the flank. Dorsal fin hyaline, with a pinkish flush. Distal half of the anal scarlet, the proximal half colourless ; anal ocelli orange-red. Caudal fin flushed with scarlet, especially intense on the distal half. Pelvics dark on the outer half, reddish-yellow mesially. Quiescent males golden-yellow shading to silvery-white ventrally ; a fairly distinct dark mid-lateral stripe and an interrupted upper stripe slightly below the insertion of the dorsal fin. Dorsal and caudal fins darkish, the anal and pelvics lighter ; anal ocelli yellow. Females and juvenile males. Ground colour and banding as above, the upper band usually broken into rather indistinct blotches. All fins light yellow, the caudal somewhat darker. Preserved material. Both sexes. Ground colour yellowish-silver to brownish, an intense, narrow mid-lateral black line extends from the upper angle of the oper- culum to the caudal peduncle and, in some specimens even on to the caudal fin ; a fainter, often interrupted black stripe runs mid-way between the upper lateral line and the dorsal fin base. In some fishes there are traces of a very faint interocular band. All fins hyaline ; in males the dorsal has dusky lappets and the pelvics are dark. Distribution. Haplochromis martini is known only from Lake Victoria. Specimens from Lake Edward once identified as Tilapia martini (Boulenger, 1914) were later referred to H. schubotzi (Regan, 1921). Ecology. Habitat. Available records (from eight localities) suggest that H. martini is restricted to water less than 40 feet deep, where the species is ubiquitous but nowhere common. The species has been found over both sand and mud bottoms, on exposed shores and in sheltered bays. There are some indications that it may not occur close inshore since the only record of H. martini in beach-operated seine nets came from an area (Majita) where the nets were shot about 300 yards off-shore. Food. Sixteen of the twenty-two specimens examined had ingested material in the stomach and intestines ; in three of these specimens, however, the contents were unidentifiable sludge. Eleven of the remaining thirteen fishes contained, as the exclusive or predominating food, the fragmentary remains of small fishes (identified in two cases as Haplochromis) ; one of these individuals had also fed on larval Diptera and another had eaten what appeared to be the foot and other soft parts of a snail. Another fish had fed only on larval Diptera and one was empty except for some small fish bones in the posterior intestine. 248 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES Breeding. Haplochromis martini is a female mouth-brooder ; females reach sexual maturity at ca. 80 mm. S.L. ; no data are available for males. Both sexes appear to attain the same maximum adult size. Affinities. Because of its strongly decurved snout, large eye and the marked posterior extension of the premaxilla, H. martini is one of the more immediately recognizable species. Yet, despite these characters H. martini retains most of the fundamental features of a generalized species such as H. macrops. On the other hand, H. martini differs from members of this species group (and probably most other Lake Victoria species) in its bright yellow coloration. When attempting to assess the phyletic affinities of H. martini one is faced with these rather contradictory characters and with the fact that, despite its generalized dentition and body-form, H. martini can be a piscivorous predator. The majority of piscivorous Haplochromis in Lake Victoria are larger than H. martini and have elongate bodies and heads ; the teeth in these species are usually large and canini- form. Taking into account the various structural and ecological characters H. martini should perhaps be considered a superficially but trophically distinct branch from the generalized stem as represented, perhaps, by an H. macrops-like ancestor. Study material and distribution records Museum and Reg. No. Locality . Collector Uganda B.M. (N.H.). 1906.5.30.463-5 . Bunjako . Degen (Lectotype and paratypes) ,, 1906.5.30.466-8 . ,, ,, (Paratypes) ,, 1959.4.28.124-132 . Pilkington Bay . E.A.F.R.O. ,, 1959.4.28.138 . Old Bukakata Bay . ,, 1959.4.28.140 . Napoleon Gulf, near Jinja . ,, Tanganyika 1959.4.28.116-123 . Majita Kenya ,, 1959.4.28.133-137 . Off Port Southby . ,, 1959.4.28.139 . Beach below Usoma Lighthouse . Haplochromis humilior (Blgr.) 1911 (Text-figs. 10 and n) Tilapia humilior Boulenger, 1911, Ann. Mus. Genova (3), 5, 74, pi. Ill, fig. 3. Tilapia lacrimosa (part), Boulenger, 1915, Cat. Afr. Fish. 3, 234. Haplochromis desfontainesii (part), Boulenger, 1915, torn, cit., 303. Haplochromis nubilus (part), Regan, 1922, Proc. zool. Soc. London, 164. Haplochromis humilior (part), Regan, 1922, op. cit., 169. ? Paratilapia granti (part), Boulenger, 1915, torn, cit., 342. A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 249 Lectotype. A male 90 mm. standard length from Kakindu, Victoria Nile, collected by Bayon (now in the collections of the Museo Civico di Storia Naturale, Genoa). Description, based on thirty specimens 65-90 mm. S.L. (including the lectotype and one paratype ; the second paratype [B.M. (N.H.) Reg. No. 1911.3.3.152] is very poorly preserved and although examined, is not included in the description). Depth of body 29-0-37-5 (M = 34-4) per cent of standard length, length of head 31-6-37-8 (M = 34-7) per cent. Dorsal head profile curved, sloping at an angle of 45-5o. Preorbital depth 13-6-17-9 (M = 16-3) per cent of head, least interorbital width 21-0-28-6 (M = 24-2) per cent. Snout as long as broad or slightly longer, its length 27-0-34-8 (M = 30-9) per cent of head, diameter of eye 27-0-32-5 (M = 30-3), depth of cheek 18-5-23-2 (M = 21-2) per cent. Caudal peduncle i5'2-i9-i (M = 17-4) per cent of standard length, 1-3-1-8 (mode 1-5) times as long as deep. FIG. 10. Haplochromis humilior, lectotype (from Boulenger, Ann. Mus. Genova). Mouth horizontal, the lower jaw often slightly shorter than the upper ; length of lower jaw 33-4-39-6 (M = 36-6) per cent of head and 1-3-2-2 (modal range 1-5-1-8) times as long as broad. Posterior tip of the maxilla extending to the vertical through the anterior orbital margin or somewhat beyond (to below the pupil in one specimen). Populations of H. humilior from different localities in the lake appear to have characteristic f acies which make any one population more or less readily identifiable ; unfortunately no means of quantifying these characters could be determined. Also, it has so far proved impossible, through lack of material, to decide whether Lake Victoria H. humilior differ from those inhabiting the Victoria Nile. Gill rakers short and stout, 6-8 (modes 6 and 7), rarely 9 on the lower part of the first arch. Scales ctenoid ; lateral line with 30 (.7), 31 (f.7), 32 (1.7) or 33 (.7) scales ; cheek with 2 or 3 (rarely 4) series. Six or 7 scales between the lateral line and the origin 250 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES of the dorsal fin, 6-8 (rarely 5 or 9) between the pectoral and pelvic fin bases. Scales on the pectoral region relatively small. Fins. Dorsal with 24 (f.6), 25 (f.2i) or 26 (.3) rays, anal with n (.4) or 12 (.24) comprising XV-XVI, 8-10 and III, 8 or 9 spinous and branched rays for the fins respectively. Pectoral 69'O-92'3 (M = 81-0) per cent of head. Caudal truncate. Teeth. The outer teeth in both jaws are moderately stout and unequally or, less frequently, sub-equally bicuspid. In fishes over 70 mm. S.L. some weakly bicuspid or even unicuspid teeth may occur ; there are 36-52 (modal range 46-48) teeth in the upper, outer series. Inner teeth are tricuspid and arranged in 2 or 3 (rarely 4) rows in the upper jaw and i or 2 (rarely 4) in the lower. A distinct space separates the inner and outer tooth series. Lower pharyngeal bone and teeth. The lower pharyngeal bone, although relatively stout is less massive than the bone in a specimen of H. ishmaeli or H. pharyngomylus 0-2 cm FIG. ii. Haplochromis humilior ; lower pharyngeal bone, occlusal view, from a Lake Victoria speci- men. 0-2 cm FIG. 12. Haplochromis theliodon ; lower pharyngeal bone, occlusal view. of the same size. Teeth in the two median rows are always enlarged, with the most posterior one or two pairs largest. There is some variation in the degree of enlarge- ment of the median teeth, which may be bicuspid, conical or even molariform ; no clear-cut correlation could be detected between, on the one hand, tooth-size and form and, on the other, the sex and size of the fish. There is, however, a tendency for larger individuals to have the coarsest median pharyngeal teeth. Sagittal sections through a number of bones (from fishes 65-70 mm. S.L.) suggest that both time and chance may influence the nature of the dentition, since unerupted replace- ment teeth are always molariform irrespective of the nature of the functional teeth which they underlie. In addition to the two median rows, the next lateral row on each side may also contain a number of molariform teeth. Coloration in life. Breeding males. Ground colour dark silvery-grey with intense dusky blotches on the head ; branchiostegal membrane dull black. A coppery flush extends over the cheek, operculum and flank as far as the origin of the anal fin. Anal and caudal fins light red, the colour becoming more intense along the A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 251 margins of both fins and the upper and lower posterior angles of the caudal ; two or three yellow anal ocelli. Dorsal fin dusky, with an orange-red margin to the soft part and red spots and bars between the rays of the posterior half of the spinous dorsal and over the entire soft part. Pelvics black. Quiescent males. General coloration as in females except that the pelvics are somewhat dusky and the un- paired fins have a pinkish flush ; anal ocelli are present. Females. Ground colour silvery-yellow. Dorsal, pelvic and anal fins pale yellow, the dorsal with red spots distributed as in males. Colour of preserved material. Males. Greyish, darker dorsally, the chest and branchiostegal membrane sooty ; in some specimens there are traces of seven or eight, narrow transverse bars on the flank and caudal peduncle. A lachrymal stripe, a pair of transverse stripes across the snout and, in some fishes, a broad band across the interorbital region are also visible, as are one or two bands on the nape. Dorsal fin variable, from hyaline to dusky. Anal hyaline in quiescent fishes and whitish in active individuals. Pelvics black (darkest in active fishes) but with a whitish overlay on the proximal half. Females silvery, some with very faint traces of vertical bars usually most obvious on the mid-lateral aspects of the flanks. All fins hyaline. Distribution. The species occurs in Lake Victoria and the Victoria Nile. Ecology. Habitat. In Lake Victoria the species is confined to shallow water over sandy beaches in both exposed and sheltered areas. No data are available for the riverine populations. Food. The gut contents of thirty-two fishes (from two localities) yielded identifi- able material. Of these specimens, twenty-four contained bottom debris (sand grains, plant fragments, diatom frustules and blue-green algae) together with remains of both larval and pupal insects (especially Diptera and Trichoptera, less frequently, Ephemeroptera) ; four fishes contained only insect remains and one only the diatom Melosira. Ten individuals had eaten, in addition to insects, both bivalves (unidentifiable) and gastropods (Melanoides sp. and Bellamy a sp.). These molluscan fragments were too finely divided to allow for any estimate of the number of animals eaten. Nevertheless it does seem, from this sample at least, that Mollusca are not a major element in the food of H. humilior. The large quantities of sand found with the remains of Trichoptera larvae in most fishes is of interest, particularly since the grains are small and of a remarkably uniform size. This suggests that the sand grains could be derived from the sand- grain cases made by certain caddis larvae. The moderately large pharyngeal mill of H. humilior may thus serve the dual purpose of crushing mollusc shells and the sand-grain cases of certain larval insects. Breeding. Nothing is known about the breeding habits of H. humilior. The smallest specimens available (a male and a female both 65 mm. S.L.) are adult ; the sexes apparently do not differ in maximum adult size attained. Affinities. Haplochromis humilior differs from the generality of small Haplochromis species in several characters, particularly in having a relatively massive lower 252 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES pharyngeal bone and in having a low modal number of gill rakers (6-7). Another pronounced difference lies in the tendency for the lower jaw to be shorter than the upper. In most other characters, H. humilior resembles H. pallidus, a species which shows incipient hypertrophy of the lower pharyngeal bone. Haplochromis humilior could be a more specialized off-shoot from an H. pallidus-like stem. Unlike many other presumed phyletic lines within the Victoria species flock, this one is not continued by one or more extant species. Haplochromis humilior does not appear to have any close relationship to the principal group of species with enlarged pharyn- geals, namely H. obtusidens, H. ishmaeli and H. pharyngomylus. Study material and distribution records Museum and Reg. No. Locality Collector Uganda Genoa Museum (C.E. 12910) . Kakindu, Victoria Nile . Bayon (Lectotype) B.M. (N.H.). 1911.3.3.152-3 . ,, (Paratypes) 1906.5.20.314 . Entebbe . Degen ,, 1959.4.28.88-107 . Beach near Nasu Point . E.A.F.R.O. ,, 1959.4.28.108 . Near Grant Bay . ,, ,, 1959.4.28.109-112 . Entebbe, Harbour Tanganyika 1959.4.28.113-115 . Majita Kenya 1909.11.15.38 . Kisumu Bay . Blayney-Percival Haplochromis riponianus (Blgr.) 1911 (Text-figs. 4 and 13) Pelmatochromis riponianus (part) Boulenger, 1911, Ann. Mus. Genova (3), 5, 69, pi. II, fig. 3 ; Idem, 1915, Cat. Afr. Fish. 3, 411, fig. 280. Haplochromis riponianus, Lohberger, 1929, Zoo/. Anz. 86, 222. Paratilapia serranus (part), Boulenger, 1915, torn, cit., 334. Paratilapia victoriana (part), Boulenger, 1915, torn, cit., 341. Haplochromis ishmaeli (part) Boulenger, 1906, Ann. Mag. nat. Hist. (7), 17, 446 ; Idem, 1915, torn. cit. 293. Haplochromis cinereus (part), Regan, 1922, Proc. zoo/. Soc. London, 166. On the basis of specimens in the Vienna Museum, Lohberger (1929) decided that Regan's views on the conspecificity of Pelmatochromis riponianus and H. cinereus could not be substantiated ; consequently he resurrected the former species as Haplochromis riponianus. I have not examined Lohberger's specimens but, from studying considerably more material than was available to either Regan or Lohberger, I can fully endorse the latter's action. Lectotype. A male 95-5 mm. standard length, from Jinja, Uganda, collected by Bayon (Genoa Museum, C.E. 12996). A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 253 Description, based on twenty-eight specimens (including the lectotype and two paratypes) 57-104 mm. S.L. One other paratype (B.M. (N.H.) Reg. No. 1911. 3 3 37) is n t included in the description. Depth of body 33-3-39-4 (M = 35-7) per cent of standard length, length of head 32-8-37-7 (M = 35-7) per cent. Dorsal head profile straight or very slightly curved, sloping at an angle of ca. 35-45. Preorbital depth 16-3-19-5 (M = 17-6) per cent of head, least interorbital width 23-0-28-1 (M = 25-1) per cent. Snout slightly longer than broad, its length 30-5-35-4 (M = 33-6) per cent of head ; diameter of eye 24-2-31-0 (M = 26-6), depth of cheek 19-2-25-0 (M = 22-7) per cent. Caudal peduncle 14-4-18-4 per cent of standard length, 1-2-1-7 times as long as deep (modal range 1-3-1-5). FIG. 13. Haplochromis viponianus ; lectotype (from Boulenger, Ann. Mus. Geneva) . Mouth horizontal or very slightly oblique, jaws equal anteriorly, the lower 33-4- 42-2 (M = 38-5) per cent of head and 1-3-2-0 (modal range 1-6-1-8) times as long as broad. Posterior tip of the maxilla extending to the vertical through the anterior orbital margin or almost so, occasionally to below the anterior quarter of the eye. Lips noticeably thickened but not produced into median lobes. Gill rakers on the first arch moderately stout in most fishes but slender in a few others, the lowermost one to three reduced and the pair nearest the epi-cerato- branchial angle often flattened and tri- or quadrifid ; 6-8 (mode 7) rakers on the lower part of the arch. Scales ctenoid ; lateral line with 30 (f.2), 31 (f.2), 32 (f.n), 33 (f-io) or 34 (f.2) scales, cheek with 3 or 4 series ; 5^-7 (rarely 5 or 8) scales between the lateral line and the dorsal fin origin ; 7 or 8 (rarely 6) between the pectoral and pelvic fin bases. Scales on the pectoral region moderate. 254 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES Fins. Dorsal with 24 (.3), 25 (.24) or 26 (f.i) rays, anal with n (.3) or 12 (f.25), comprising XV-XVI, 9-10 and III, 8 or 9 spinous and branched rays for the fins respectively. Pectoral 69-0-88-5 (M = 78-5) per cent of head. Caudal sub-truncate. Teeth. The outer teeth in both jaws are relatively slender and slightly to strongly recurved ; the basic cusp pattern is unequally bicuspid, but the crowns are often so worn that the teeth appear to be weakly cuspidate or even unicuspid and bluntly incisiform. In some fishes over 80 mm. S.L. initially unicuspid teeth occur and may even be the predominating form in fishes more than 100 mm. S.L. The number of teeth in the upper, outer rows shows slight positive allometry with standard length ; there are 38-62 teeth in this row. Unicuspid and weakly tricuspid teeth are found in the inner rows ; often both types of teeth occur together, especially in fishes over 80 mm. S.L. The inner teeth are implanted at an angle and may be buried in the thickened oral mucosa (possibly a preservation artefact). In the upper jaw, the inner teeth are arranged in 3 or 4 (rarely 2) rows and in the lower in 2-4 (rarely i) rows. Boulenger's description (1911 and 1915) of the inner teeth as " minute " appears to stem from his being misled by the thickened oral epithelium which has hidden all but the tips of these teeth. Lower pharyngeal bone and teeth. The lower pharyngeal bone is triangular and in most specimens fairly stout. The relative degree to which the bone is enlarged is somewhat greater than that of the lower pharyngeal in H. humilior (see p. 250). In a few fishes, however, the bone is slender. This variation in stoutness is not entirely correlated with size since, although the smallest specimens have slender or but slightly thickened bones, some of the larger fishes do not have proportionately enlarged pharyngeals. The form of the teeth in the four median rows does show correlation with both the size of the individual and the stoutness of the bone. In fishes less than ca. 70 mm. S.L. some of the posterior teeth in the two median rows are enlarged ; in fishes 70- 80 mm. most of the median teeth are enlarged as are some or all of the teeth in the row on each side of the two median rows. Next, in specimens above 80 mm. S.L. (except those with slender pharyngeal bones) the teeth of these four rows are larger still, whilst those in the two median rows tend to be molariform. Finally, in fishes over 98 mm. S.L. some of the more lateral teeth are also molariform. Large indi- viduals with slender lower pharyngeals have only slightly enlarged median teeth, comparable with those of the smaller (< 90 mm.) specimens described above. Osteology. The shape of the neurocranium departs from the generalized type towards the form found in the elongated, piscivorous predators (as typified by H. mento). In H. riponianus, the slope from the anterior tip of the vomer to the base of the supraoccipital crest is less steep and more nearly straight than in the generalized type of skull ; also, the preorbital region in H. riponianus is relatively longer than in, for example, the skull of H. obliquidens or H. macrops. Coloration. The colours of live fishes are unknown. Preserved material. Sexually active males. Ground colour greyish-brown, chest dusky ; a dark lachrymal stripe and faint traces of four interrupted transverse bars on the flanks. Dorsal, caudal and anal fins hyaline, the anal with two or three A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 255 dead-white ocelli, usually arranged in a single row, but occasionally in two rows. Pelvic fins black. Immature males similar to females but with darker pel vies and small, distinct ocelli on the anal fin. Females silvery-grey shading to silver ventrally ; six to ten transverse bars of variable width (narrowest when most numerous) across the flanks and caudal peduncle ; sometimes, a very faint lachrymal stripe. All fins hyaline, the caudal occasionally maculate ; in a few specimens there are one or two, small, dead- white spots in the same position as the ocelli on the anal fin of males. Distribution. Lake Victoria and possibly the Victoria Nile. The latter locality is surmised from the data given in the original description of the species. In that paper (Boulenger, 1911), the locality is given only as Jinja, Ripon Falls, but in the introduction Boulenger implies that the entire collection, of which H. riponianus formed part, was from the Victoria Nile, that is below the Ripon Falls. Later (Cat. Afr. Fish. 3, 1914) the type locality is given more specifically as " Ripon Falls, Victoria Nile." Ecology. Habitat. The species is apparently confined to sand or rock substrates in the littoral regions of the lake ; it has been caught in both exposed and sheltered localities. Food. Stomach and intestinal contents of thirty-two fishes (from one locality) show that at least this population of H. riponianus was mainly insectivorous, although some fishes had also fed on Mollusca. Insect larvae (especially Trichoptera and Ephemeroptera) were found in every fish. As in H. humilior (see p. 251) large quantities of uniformly sized sand-grains were found in the intestines of most fishes. Since these grains closely resemble those forming the cases of certain Caddis-fly larvae found intact in some individuals, it is suggested that the sand was derived, at least partly, from crushed cases. In addition to the main contents listed above, eight fishes contained relatively large quantities of crushed bivalve shells (? Corbicula sp.) ; a few fragments of gastropod shells were also found in these individuals. Breeding. No information is available on the breeding habits of H. riponianus. The smallest sexually mature fish is a female 84 mm. S.L. ; the smallest adult male is 86 mm. S.L. Affinities. In combination, the oral and pharyngeal dentition set H. riponianus apart from other Lake Victoria species. In appearance and in possessing a similar oral dentition, H. saxicola (see p. 257) appears to be the nearest relative of H. riponianus although it differs in having a relatively slender pharyngeal bone with only the two median tooth rows slightly enlarged. The two species, which differ somewhat in their ecological relationships, may represent separate adaptive lines derived from a common ancestor. Haplochromis pallidus seems structurally suited for consideration as the extant representative of the presumed ancestor. (See also p. 235.) Although the lower pharyngeal bone and its dentition are similar in H . humilior and H. riponianus and although both species have very similar ecological require- 256 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES ments, the species show quite marked divergence in body-form (especially head shape) and oral dentition. What relationships there are probably lie far back in their phylogenetic history ; certainly the two species cannot be considered members of a recently evolved phyletic line. Boulenger's view (1911) that H. riponianus and H. microdon are closely related can no longer be held ; the two species have very different phylogenies, as witnessed by several anatomical and osteological characters, and equally distinctive habits (Greenwood, 1959). Boulenger was undoubtedly misled by the supposedly small teeth of both species (Greenwood, op. cit., and above) whereas in fact the teeth of H. riponianus are not minute and are of a markedly different form from those of H. microdon. Study material and distribution records Museum and Reg. No. Locality - Collector Uganda Genoa Museum (C.E. 12996 . Jinja, Ripon Falls . Bayon (Lectotype) B.M. (N.H.). 1911-3- 3- 37-39 1911.3.3.24 1906.5.30.280 . Entebbe . Degen 1906.5.30.394 . Bunjako . (Paratype H. ishmaeli) 1929.8.13.1 . Entebbe . Hoare 1959.4.28.141-157 . Entebbe, Airport beach . E.A.F.R.O. 1959.4.28.158 . Hannington Bay . ,, ,, 1959.4.28.159 . Buka Bay . ,, 1959.4.28.160-162 . Entebbe, Harbour . Lake Victoria, Locality Unknown 1901.6.24.86-87 . . Sir H. Johnson 1928.5.24.136-138 . . M.Graham Haplochromis saxicola,, sp. nov. (Text-figs. 5 and 14) Pelmatochromis riponianus (part) Boulenger, 1911, Ann. Mus. Genova (3), 5, 69 ; Idem, 1915, Cat. Afr. Fish. 3, 411. Haplochromis cinereus (part) Regan, 1922, Proc. zool. Soc. London, 166. Holotype. A female in-o + 25-0 mm. long (B.M. (N.H.) Reg. No. 1959.4.28.249) from Ramafuta island, Uganda. Description, based on twenty-seven specimens (including the holotype of the species and two paratypes of Pelmatochromis riponianus) 106-123 mm. S.L. Depth of body 34-8-42-5 (M = 37-8) per cent of standard length, length of head 35-3-42-5 (M = 37-8) per cent. Dorsal head profile straight or gently curved, sloping at ca. 3O-4O. Preorbital depth 15-2-19-0 (M = 17-6) per cent of head, A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 257 least interorbital width 23-9-29-8 (M = 26-9) per cent. Snout slightly longer than broad or, less commonly, as long as broad, its length 34-0-41-8 (M = 37-5) per cent of head ; diameter of eye 20-4-26-8 (M = 24-4), depth of cheek 21-4-26-2 (M = 23-9) per cent. Caudal peduncle 13-1-17-7 (M = 15-4) per cent of standard length, i-o- 1-5 (mode 1-3) times as long as deep. Mouth horizontal or very slightly oblique ; lips variably thickened but always noticeably enlarged. Lower jaw 39-7-46-5 (M = 43-0) per cent of head and 1-5- 1-9 (mode 1-8) times as long as broad. Posterior tip of the maxilla reaching or almost reaching the vertical through the anterior orbital margin, sometimes extending to below the eye. Gill rakers moderately stout, the uppermost two or three either slender or divided FIG. 14. Haplochromis saxicola ; holotype. Drawn by John Norris Wood. and somewhat flattened, the lowermost one to three usually reduced ; 7-9 (mode 8) rarely 6 on the lower part of the first arch. Scales ctenoid; 31 (f.2), 32 (1.15), 33 (f-9) or 34 (f.i) in the lateral line ; cheek with 3 or 4 series. Six or 7 (rarely 5) between the lateral line and the dorsal fin origin ; 6-8 (rarely 5 or 9) between the pectoral and pelvic fin bases. Scales on the pectoral region small. Fins. Dorsal with 24 (1.4), 25 (f.2o) or 26 (f.2) rays, anal with n (f.i), 12 (f.24) or 13 (f.i), comprising XIV-XVI, 9 or 10 and III, 8-10 spinous and branched rays for the fins respectively. One specimen has XVI, 6 rays in the dorsal and another II, 8 in the anal. Pectoral 67-8-81-0 (M = 74-5) per cent of head. Caudal truncate or sub-truncate. Teeth, In the outer series of each jaw the teeth are slender, recurved and generally unicuspid, but a few weakly bicuspid teeth may occur in fishes less than 115 mm. S.L. 258 A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES The crowns of the teeth are often worn so as to assume a bluntly incisiform shape. There are 52-68 teeth in the outer row of the upper jaw (modal range 60-62). The inner tooth rows are composed of obliquely implanted and either unicuspid or both uni- and tricuspid teeth arranged in 2 or 3 (rarely 4 or 5) rows in each jaw. The dentition of H. saxicola bears a very strong resemblance to that of H. ripon- ianus, the major difference lying in the higher percentage of primarily unicuspid teeth in H, saxicola. However, it must be borne in mind that no available specimens of H. riponianus are as large as even the smallest H. saxicola. Lower pharyngeal bone and teeth. In ninety per cent of specimens examined, the lower pharyngeal bone is not enlarged ; in the remaining ten per cent it is somewhat thickened and resembles the lower pharyngeal of H. riponianus. The two median tooth rows are slightly enlarged in all specimens and may even be molariform in those individuals with enlarged lower pharyngeal bones. Very exceptionally, the median teeth are not noticeably larger than the more lateral ones. Osteology. The neurocranium of H. saxicola is very like that of H. riponianus (see p. 254) ; the premaxilla is, however, distinctive for its noticeably arched dentigerous arms which impart a characteristic peak to the antero-medial part of the bone. Coloration in life. Sexually active males. Ground colour dark grey-green, some scales on the flank with golden centres ; chest and branchiostegal membrane black ; a coppery-red flush on the operculum and flanks. Dorsal fin dark, lappets and maculae red ; caudal blue-grey with red posterior and ventral margins ; anal fin blue-grey, suffused with pink, especially the distal margins, ocelli bright yellow ; pelvic fins black. Quiescent males pale silvery-blue, almost grey dorsally ; some flank scales with golden centres, pectoral region silver. Dorsal, caudal and pelvic fins hyaline, the dorsal with pale red lappets and margin to the soft part, pelvics dusky on the lateral half, hyaline mesially. Females. Ground colour golden-grey ; all fins hyaline. Preserved material. Adult males (probably sexually active). Ground coloration dark grey-black, especially dark on the head, dorsal aspects of the flanks and along the ventral body surface. Lips light grey ; branchiostegal membrane black. Dorsal fin dark, with light maculae on the soft part. Anal fin black on the basal third, the distal two-thirds yellowish, with two grey ocelli. Caudal greyish ventrally, yellow around the margin. Females, juvenile and some apparently adult (? quiescent] males. Brownish-yellow ground coloration, darkest on the dorsal surface of the head ; four to seven, fairly narrow dark transverse bars on the flanks and caudal peduncle. Dorsal and caudal fins greyish, all other fins colourless, except for the black pelvics in adult males. Distribution. The species is known definitely from Lake Victoria but may also occur in the Victoria Nile. This locality is suggested by the presumed provenance of two P. riponianus paratypes now considered to be H. saxicola. For further dis- cussion, see under " Distribution " in H. riponianus, p. 255. Ecology. Habitat. The habitats in which H. saxicola has been caught are rather more varied than is common for most Lake Victoria Haplochromis. The species A REVISION OF THE LAKE VICTORIA HAPLOCHROMIS SPECIES 259 occurs in shallow water over exposed sand or shingle beaches, amongst dense plant stands near rocky shores and over shingle and small boulders in water 10-30 feet deep. Finally, one specimen was caught more than a mile off-shore in nets set on a mud bottom in water ca. 180 feet deep. The most consistent factors in all these habitats (except the latter) are the hard substrates of sand, rock or shingle. Food. Twenty-six fishes (from nine different localities) were examined ; of these, only twelve contained any ingeste